Bug 958868 - Add support for delta line and page accumulation; r=masayuki, sr=smaug
authorAndrew Comminos <andrew@morlunk.com>
Mon, 07 Jul 2014 18:54:14 +0900
changeset 214586 1113df431eab55cb5f9b42d652d6eea89cd71e01
parent 214585 eebc0e885bb36aba9c309934bc8da5a8de51e626
child 214587 2ec6c5b1d1d2c68c7a836e01f909d8532ec07595
push id515
push userraliiev@mozilla.com
push dateMon, 06 Oct 2014 12:51:51 +0000
treeherdermozilla-release@267c7a481bef [default view] [failures only]
perfherder[talos] [build metrics] [platform microbench] (compared to previous push)
reviewersmasayuki, smaug
bugs958868
milestone33.0a1
first release with
nightly linux32
nightly linux64
nightly mac
nightly win32
nightly win64
last release without
nightly linux32
nightly linux64
nightly mac
nightly win32
nightly win64
Bug 958868 - Add support for delta line and page accumulation; r=masayuki, sr=smaug
dom/base/nsDOMWindowUtils.cpp
dom/events/EventStateManager.cpp
dom/events/EventStateManager.h
dom/events/test/test_continuous_wheel_events.html
dom/interfaces/base/nsIDOMWindowUtils.idl
services/sync/tps/extensions/mozmill/resource/stdlib/EventUtils.js
testing/mochitest/tests/SimpleTest/EventUtils.js
widget/MouseEvents.h
widget/nsGUIEventIPC.h
widget/windows/nsWinGesture.cpp
--- a/dom/base/nsDOMWindowUtils.cpp
+++ b/dom/base/nsDOMWindowUtils.cpp
@@ -874,22 +874,18 @@ nsDOMWindowUtils::SendWheelEvent(float a
   WidgetWheelEvent wheelEvent(true, NS_WHEEL_WHEEL, widget);
   wheelEvent.modifiers = GetWidgetModifiers(aModifiers);
   wheelEvent.deltaX = aDeltaX;
   wheelEvent.deltaY = aDeltaY;
   wheelEvent.deltaZ = aDeltaZ;
   wheelEvent.deltaMode = aDeltaMode;
   wheelEvent.isMomentum =
     (aOptions & WHEEL_EVENT_CAUSED_BY_MOMENTUM) != 0;
-  wheelEvent.isPixelOnlyDevice =
-    (aOptions & WHEEL_EVENT_CAUSED_BY_PIXEL_ONLY_DEVICE) != 0;
-  NS_ENSURE_TRUE(
-    !wheelEvent.isPixelOnlyDevice ||
-      aDeltaMode == nsIDOMWheelEvent::DOM_DELTA_PIXEL,
-    NS_ERROR_INVALID_ARG);
+  wheelEvent.mIsNoLineOrPageDelta =
+    (aOptions & WHEEL_EVENT_CAUSED_BY_NO_LINE_OR_PAGE_DELTA_DEVICE) != 0;
   wheelEvent.customizedByUserPrefs =
     (aOptions & WHEEL_EVENT_CUSTOMIZED_BY_USER_PREFS) != 0;
   wheelEvent.lineOrPageDeltaX = aLineOrPageDeltaX;
   wheelEvent.lineOrPageDeltaY = aLineOrPageDeltaY;
   wheelEvent.widget = widget;
 
   wheelEvent.time = PR_Now() / 1000;
 
--- a/dom/events/EventStateManager.cpp
+++ b/dom/events/EventStateManager.cpp
@@ -5091,38 +5091,37 @@ EventStateManager::DeltaAccumulator::Ini
     if (duration.ToMilliseconds() > WheelTransaction::GetTimeoutTime()) {
       Reset();
     }
   }
   // If we have accumulated delta,  we may need to reset it.
   if (IsInTransaction()) {
     // If wheel event type is changed, reset the values.
     if (mHandlingDeltaMode != aEvent->deltaMode ||
-        mHandlingPixelOnlyDevice != aEvent->isPixelOnlyDevice) {
+        mIsNoLineOrPageDeltaDevice != aEvent->mIsNoLineOrPageDelta) {
       Reset();
     } else {
       // If the delta direction is changed, we should reset only the
       // accumulated values.
       if (mX && aEvent->deltaX && ((aEvent->deltaX > 0.0) != (mX > 0.0))) {
         mX = mPendingScrollAmountX = 0.0;
       }
       if (mY && aEvent->deltaY && ((aEvent->deltaY > 0.0) != (mY > 0.0))) {
         mY = mPendingScrollAmountY = 0.0;
       }
     }
   }
 
   mHandlingDeltaMode = aEvent->deltaMode;
-  mHandlingPixelOnlyDevice = aEvent->isPixelOnlyDevice;
-
-  // If it's handling neither pixel scroll mode for pixel only device nor
-  // delta values multiplied by prefs, we must not modify lineOrPageDelta
+  mIsNoLineOrPageDeltaDevice = aEvent->mIsNoLineOrPageDelta;
+
+  // If it's handling neither a device that does not provide line or page deltas
+  // nor delta values multiplied by prefs, we must not modify lineOrPageDelta
   // values.
-  if (!(mHandlingDeltaMode == nsIDOMWheelEvent::DOM_DELTA_PIXEL &&
-        mHandlingPixelOnlyDevice) &&
+  if (!mIsNoLineOrPageDeltaDevice &&
       !EventStateManager::WheelPrefs::GetInstance()->
         NeedToComputeLineOrPageDelta(aEvent)) {
     // Set the delta values to mX and mY.  They would be used when above block
     // resets mX/mY/mPendingScrollAmountX/mPendingScrollAmountY if the direction
     // is changed.
     // NOTE: We shouldn't accumulate the delta values, it might could cause
     //       overflow even though it's not a realistic situation.
     if (aEvent->deltaX) {
@@ -5173,17 +5172,17 @@ EventStateManager::DeltaAccumulator::Ini
 }
 
 void
 EventStateManager::DeltaAccumulator::Reset()
 {
   mX = mY = 0.0;
   mPendingScrollAmountX = mPendingScrollAmountY = 0.0;
   mHandlingDeltaMode = UINT32_MAX;
-  mHandlingPixelOnlyDevice = false;
+  mIsNoLineOrPageDeltaDevice = false;
 }
 
 nsIntPoint
 EventStateManager::DeltaAccumulator::ComputeScrollAmountForDefaultAction(
                      WidgetWheelEvent* aEvent,
                      const nsIntSize& aScrollAmountInDevPixels)
 {
   MOZ_ASSERT(aEvent);
--- a/dom/events/EventStateManager.h
+++ b/dom/events/EventStateManager.h
@@ -697,33 +697,33 @@ protected:
      */
     nsIntPoint ComputeScrollAmountForDefaultAction(
                  WidgetWheelEvent* aEvent,
                  const nsIntSize& aScrollAmountInDevPixels);
 
   private:
     DeltaAccumulator() :
       mX(0.0), mY(0.0), mPendingScrollAmountX(0.0), mPendingScrollAmountY(0.0),
-      mHandlingDeltaMode(UINT32_MAX), mHandlingPixelOnlyDevice(false)
+      mHandlingDeltaMode(UINT32_MAX), mIsNoLineOrPageDeltaDevice(false)
     {
     }
 
     double mX;
     double mY;
 
     // When default action of a wheel event is scroll but some delta values
     // are ignored because the computed amount values are not integer, the
     // fractional values are saved by these members.
     double mPendingScrollAmountX;
     double mPendingScrollAmountY;
 
     TimeStamp mLastTime;
 
     uint32_t mHandlingDeltaMode;
-    bool mHandlingPixelOnlyDevice;
+    bool mIsNoLineOrPageDeltaDevice;
 
     static DeltaAccumulator* sInstance;
   };
 
   // end mousewheel functions
 
   /*
    * When a touch gesture is about to start, this function determines what
--- a/dom/events/test/test_continuous_wheel_events.html
+++ b/dom/events/test/test_continuous_wheel_events.html
@@ -103,51 +103,51 @@ function prepareScrollUnits()
 // accumulated delta values of pixel scroll events of pixel only device
 // become over the line height.
 function testContinuousTrustedEvents()
 {
   const kSynthesizedWheelEventTests = [
     { description: "Simple horizontal wheel event by pixels (16.0 - 1) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 16.0, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 16.0, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 1 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 16 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
     { description: "Simple horizontal wheel event by pixels (16.0 - 1) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 16.0, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 16.0, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 1 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 16 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
     { description: "Simple horizontal wheel event by pixels (16.0 - 1) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 16.0, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 16.0, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 1 },
@@ -155,51 +155,51 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 16 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
 
     { description: "Simple vertical wheel event by pixels (16.0 - 1) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: 16.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: 16.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false,  preventDefault: false, detail: 0 },
         vertical:   { expected: true,   preventDefault: false, detail: 1 } },
       MozMousePixelScroll: {
         horizontal: { expected: false,  preventDefault: false, detail: 0 },
         vertical:   { expected: true,   preventDefault: false, detail: 16 } }
     },
     { description: "Simple vertical wheel event by pixels (16.0 - 1) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: 16.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: 16.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false,  preventDefault: false, detail: 0 },
         vertical:   { expected: true,   preventDefault: false, detail: 1 } },
       MozMousePixelScroll: {
         horizontal: { expected: false,  preventDefault: false, detail: 0 },
         vertical:   { expected: true,   preventDefault: false, detail: 16 } }
     },
     { description: "Simple vertical wheel event by pixels (16.0 - 1) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: 16.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: 16.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false,  preventDefault: false, detail: 0 },
@@ -207,17 +207,17 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: false,  preventDefault: false, detail: 0 },
         vertical:   { expected: true,   preventDefault: false, detail: 16 } }
     },
 
     { description: "Simple z-direction wheel event by pixels (16.0 - 1)",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: 0.0, deltaZ: 16.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: 0.0, deltaZ: 16.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false,  preventDefault: false, detail: 0 },
@@ -225,51 +225,51 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: false,  preventDefault: false, detail: 0 },
         vertical:   { expected: false,  preventDefault: false, detail: 0 } }
     },
 
     { description: "Simple horizontal wheel event by pixels (-16.0 - -1) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: -16.0, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: -1, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: -1, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -16.0, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -1 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -16 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
     { description: "Simple horizontal wheel event by pixels (-16.0 - -1) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: -16.0, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: -1, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: -1, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -16.0, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -1 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -16 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
     { description: "Simple horizontal wheel event by pixels (-16.0 - -1) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: -16.0, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: -1, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: -1, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -16.0, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -1 },
@@ -277,51 +277,51 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -16 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
 
     { description: "Simple vertical wheel event by pixels (-16.0 - -1) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: -16.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: -1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: -1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: -16.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false,  preventDefault: false, detail: 0 },
         vertical:   { expected: true,   preventDefault: false, detail: -1 } },
       MozMousePixelScroll: {
         horizontal: { expected: false,  preventDefault: false, detail: 0 },
         vertical:   { expected: true,   preventDefault: false, detail: -16 } }
     },
     { description: "Simple vertical wheel event by pixels (-16.0 - -1) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: -16.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: -1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: -1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: -16.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false,  preventDefault: false, detail: 0 },
         vertical:   { expected: true,   preventDefault: false, detail: -1 } },
       MozMousePixelScroll: {
         horizontal: { expected: false,  preventDefault: false, detail: 0 },
         vertical:   { expected: true,   preventDefault: false, detail: -16 } }
     },
     { description: "Simple vertical wheel event by pixels (-16.0 - -1) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: -16.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: -1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: -1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: -16.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false,  preventDefault: false, detail: 0 },
@@ -329,17 +329,17 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: false,  preventDefault: false, detail: 0 },
         vertical:   { expected: true,   preventDefault: false, detail: -16 } }
     },
 
     { description: "Simple z-direction wheel event by pixels (-16.0 - -1)",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: 0.0, deltaZ: -16.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: 0.0, deltaZ: -16.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false,  preventDefault: false, detail: 0 },
@@ -348,85 +348,85 @@ function testContinuousTrustedEvents()
         horizontal: { expected: false,  preventDefault: false, detail: 0 },
         vertical:   { expected: false,  preventDefault: false, detail: 0 } }
     },
 
     // 3 scroll events per line, and legacy line scroll will be fired first.
     { description: "Horizontal wheel event by pixels (5.3 - 1) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 5.3, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 5.3, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 1 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 5 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
     { description: "Horizontal wheel event by pixels (5.3 - 0) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 5.3, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 5.3, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 1 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 5 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
     { description: "Vertical wheel event by pixels (5.3 - 1) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: 5.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: 5.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: 1 } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: 5 } }
     },
     { description: "Vertical wheel event by pixels (5.3 - 0) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: 5.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: 5.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: 5 } }
     },
     { description: "Vertical wheel event by pixels (5.3 - 0) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: 5.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: 5.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
@@ -434,51 +434,51 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: 5 } }
     },
 
     { description: "Horizontal wheel event by pixels (-5.3 - -1) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: -5.3, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: -1, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: -1, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -5.3, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -1 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -5 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
     { description: "Horizontal wheel event by pixels (-5.3 - 0) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: -5.3, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -5.3, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -5 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
     { description: "Horizontal wheel event by pixels (-5.3 - 0) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: -5.3, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -5.3, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
@@ -486,51 +486,51 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -5 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
 
     { description: "Vertical wheel event by pixels (-5.3 - -1) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: -5.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: -1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: -1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: -5.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: -1 } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: -5 } }
     },
     { description: "Vertical wheel event by pixels (-5.3 - 0) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: -5.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: -5.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: -5 } }
     },
     { description: "Vertical wheel event by pixels (-5.3 - 0) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: -5.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: -5.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
@@ -539,51 +539,51 @@ function testContinuousTrustedEvents()
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: -5 } }
     },
 
     // 3 scroll events per line, and legacy line scroll will be fired last.
     { description: "Horizontal wheel event by pixels (5.3 - 0) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 5.3, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 5.3, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 5 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
     { description: "Horizontal wheel event by pixels (5.3 - 0) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 5.3, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 5.3, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 5 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
     { description: "Horizontal wheel event by pixels (5.3 - 1) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 5.3, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 5.3, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 1 },
@@ -591,51 +591,51 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 5 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
 
     { description: "Vertical wheel event by pixels (5.3 - 0) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: 5.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: 5.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: 5 } }
     },
     { description: "Vertical wheel event by pixels (5.3 - 0) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: 5.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: 5.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: 5 } }
     },
     { description: "Vertical wheel event by pixels (5.3 - 1) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: 5.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: 5.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
@@ -643,51 +643,51 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: 5 } }
     },
 
     { description: "Horizontal wheel event by pixels (-5.3 - 0) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: -5.3, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -5.3, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -5 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
     { description: "Horizontal wheel event by pixels (-5.3 - 0) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: -5.3, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -5.3, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -5 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
     { description: "Horizontal wheel event by pixels (-5.3 - 1) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: -5.3, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: -1, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: -1, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -5.3, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -1 },
@@ -695,51 +695,51 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -5 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
 
     { description: "Vertical wheel event by pixels (-5.3 - 0) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: -5.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: -5.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: -5 } }
     },
     { description: "Vertical wheel event by pixels (-5.3 - 0) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: -5.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: -5.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: -5 } }
     },
     { description: "Vertical wheel event by pixels (-5.3 - -1) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: -5.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: -1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: -1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: -5.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
@@ -748,51 +748,51 @@ function testContinuousTrustedEvents()
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: -5 } }
     },
 
     // Oblique scroll.
     { description: "To bottom-right wheel event by pixels (5.3/5.2 - 1/1) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 5.3, deltaY: 5.2, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 5.3, deltaY: 5.2, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 1 },
         vertical:   { expected: true,  preventDefault: false, detail: 1 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 5 },
         vertical:   { expected: true,  preventDefault: false, detail: 5 } }
     },
     { description: "To bottom-right wheel event by pixels (5.3/5.2 - 0/0) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 5.3, deltaY: 5.2, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 5.3, deltaY: 5.2, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 5 },
         vertical:   { expected: true,  preventDefault: false, detail: 5 } }
     },
     { description: "To bottom-right wheel event by pixels (5.3/5.2 - 0/0) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 5.3, deltaY: 5.2, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 5.3, deltaY: 5.2, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
@@ -800,51 +800,51 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 5 },
         vertical:   { expected: true,  preventDefault: false, detail: 5 } }
     },
 
     { description: "To bottom-left wheel event by pixels (-5.3/5.3 - -1/1) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: -5.3, deltaY: 5.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: -1, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: -1, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -5.3, deltaY: 5.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -1 },
         vertical:   { expected: true,  preventDefault: false, detail:  1 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -5 },
         vertical:   { expected: true,  preventDefault: false, detail:  5 } }
     },
     { description: "To bottom-left wheel event by pixels (-5.3/5.3 - 0/0) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: -5.3, deltaY: 5.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -5.3, deltaY: 5.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail:  0 },
         vertical:   { expected: false, preventDefault: false, detail:  0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -5 },
         vertical:   { expected: true,  preventDefault: false, detail:  5 } }
     },
     { description: "To bottom-left wheel event by pixels (-5.3/5.3 - 0/0) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: -5.3, deltaY: 5.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -5.3, deltaY: 5.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail:  0 },
@@ -852,51 +852,51 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -5 },
         vertical:   { expected: true,  preventDefault: false, detail:  5 } }
     },
 
     { description: "To top-left wheel event by pixels (-5.2/-5.3 - -1/-1) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: -5.2, deltaY: -5.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: -1, lineOrPageDeltaY: -1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: -1, lineOrPageDeltaY: -1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -5.2, deltaY: -5.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -1 },
         vertical:   { expected: true,  preventDefault: false, detail: -1 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -5 },
         vertical:   { expected: true,  preventDefault: false, detail: -5 } }
     },
     { description: "To top-left wheel event by pixels (-5.2/-5.3 - 0/0) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: -5.2, deltaY: -5.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -5.2, deltaY: -5.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail:  0 },
         vertical:   { expected: false, preventDefault: false, detail:  0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -5 },
         vertical:   { expected: true,  preventDefault: false, detail: -5 } }
     },
     { description: "To top-left wheel event by pixels (-5.2/-5.3 - 0/0) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: -5.2, deltaY: -5.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -5.2, deltaY: -5.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail:  0 },
@@ -904,34 +904,34 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -5 },
         vertical:   { expected: true,  preventDefault: false, detail: -5 } }
     },
 
     { description: "To top-right wheel event by pixels (5.3/-5.3 - 1/-1) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 5.3, deltaY: -5.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: -1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: -1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 5.3, deltaY: -5.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail:  1 },
         vertical:   { expected: true,  preventDefault: false, detail: -1 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail:  5 },
         vertical:   { expected: true,  preventDefault: false, detail: -5 } }
     },
     { description: "To top-right wheel event by pixels (5.3/-5.3 - 0/0) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 5.3, deltaY: -5.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 5.3, deltaY: -5.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail:  0 },
@@ -942,136 +942,136 @@ function testContinuousTrustedEvents()
     },
 
     // Pixel scroll only device's test. the lineOrPageDelta values should be computed
     // by ESM. When changing the direction for each delta value, it should be
     // reset at that time.
     { description: "Pixel only device's horizontal wheel event by pixels (5.3 - 0) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 5.3, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: true,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: true,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 5.3, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 5 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
     { description: "Pixel only device's horizontal wheel event by pixels (5.3 - 0) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 5.3, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: true,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: true,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 5.3, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 5 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
     { description: "Pixel only device's horizontal wheel event by pixels (5.3 - 0) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 5.3, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: true,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: true,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 5.3, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 1 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 5 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
     { description: "Pixel only device's Vertical wheel event by pixels (5.3 - 0) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: 5.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: true,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: true,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: 5.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: 5 } }
     },
     { description: "Pixel only device's Vertical wheel event by pixels (5.3 - 0) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: 5.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: true,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: true,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: 5.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: 5 } }
     },
     { description: "Pixel only device's Vertical wheel event by pixels (5.3 - 0) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: 5.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: true,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: true,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: 5.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: 5 } }
     },
     { description: "Pixel only device's Vertical wheel event by pixels (5.3 - 0) #4",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: 1.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: true,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: true,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: 1.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: 1 } }
     },
     { description: "Pixel only device's Vertical wheel event by pixels (5.3 - 1) #5",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: 5.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: true,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: true,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: 5.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
@@ -1079,51 +1079,51 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: 5 } }
     },
 
     { description: "Pixel only device's horizontal wheel event by pixels (-5.3 - 0) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: -5.3, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: true,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: true,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -5.3, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: -1 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -5 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
     { description: "Pixel only device's horizontal wheel event by pixels (-5.3 - 0) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: -5.3, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: true,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: true,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -5.3, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -5 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
     { description: "Pixel only device's horizontal wheel event by pixels (-5.3 - 0) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: -5.3, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: true,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: true,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -5.3, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -1 },
@@ -1131,85 +1131,85 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -5 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
 
     { description: "Pixel only device's Vertical wheel event by pixels (-5.3 - 0) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: -5.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: true,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: true,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: -5.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: -5 } }
     },
     { description: "Pixel only device's Vertical wheel event by pixels (-5.3 - 0) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: -5.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: true,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: true,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: -5.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: -5 } }
     },
     { description: "Pixel only device's Vertical wheel event by pixels (-5.3 - 0) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: -5.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: true,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: true,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: -5.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: -5 } }
     },
     { description: "Pixel only device's Vertical wheel event by pixels (-5.3 - 0) #4",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: -1.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: true,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: true,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: -1.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: -1 } }
     },
     { description: "Pixel only device's Vertical wheel event by pixels (-5.3 - -1) #5",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 0.0, deltaY: -5.3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: true,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: true,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: -5.3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
@@ -1219,51 +1219,51 @@ function testContinuousTrustedEvents()
         vertical:   { expected: true,  preventDefault: false, detail: -5 } }
     },
 
     // ESM should reset an accumulated delta value only when the direction of it
     // is changed but shouldn't reset the other delta.
     { description: "Pixel only device's bottom-right wheel event by pixels (5.3/4.9 - 0/0) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 5.3, deltaY: 4.9, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: true,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: true,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 5.3, deltaY: 4.9, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 5 },
         vertical:   { expected: true,  preventDefault: false, detail: 4 } }
     },
     { description: "Pixel only device's bottom-right wheel event by pixels (5.3/4.9 - 0/0) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 5.3, deltaY: 4.9, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: true,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: true,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 5.3, deltaY: 4.9, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 5 },
         vertical:   { expected: true,  preventDefault: false, detail: 4 } }
     },
     { description: "Pixel only device's bottom-left wheel event by pixels (-5.3/4.9 - 0/0) #4",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: -5.3, deltaY: 4.9, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: true,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: true,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -5.3, deltaY: 4.9, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
@@ -1271,17 +1271,17 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -5 },
         vertical:   { expected: true,  preventDefault: false, detail: 4 } }
     },
     // the accumulated X should be 0 here, but Y shouldn't be reset.
     { description: "Pixel only device's bottom-right wheel event by pixels (5.3/4.9 - 0/0) #5",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 5.3, deltaY: 1.9, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: true,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: true,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 5.3, deltaY: 1.9, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
@@ -1289,51 +1289,51 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 5 },
         vertical:   { expected: true,  preventDefault: false, detail: 1 } }
     },
 
     { description: "Pixel only device's top-left wheel event by pixels (-5.3/-4.9 - 0/0) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: -5.3, deltaY: -4.9, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: true,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: true,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -5.3, deltaY: -4.9, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -5 },
         vertical:   { expected: true,  preventDefault: false, detail: -4 } }
     },
     { description: "Pixel only device's top-left wheel event by pixels (-5.3/-4.9 - 0/0) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: -5.3, deltaY: -4.9, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: true,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: true,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -5.3, deltaY: -4.9, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -5 },
         vertical:   { expected: true,  preventDefault: false, detail: -4 } }
     },
     { description: "Pixel only device's bottom-left wheel event by pixels (-5.3/4.9 - 0/0) #4",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: -5.3, deltaY: 4.9, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: true,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: true,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -5.3, deltaY: 4.9, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -1 },
@@ -1341,17 +1341,17 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -5 },
         vertical:   { expected: true,  preventDefault: false, detail:  4 } }
     },
     // the accumulated Y should be 0 here, but X shouldn't be reset.
     { description: "Pixel only device's top-left wheel event by pixels (-5.3/-4.9 - 0/0) #5",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: -5.3, deltaY: -4.9, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: true,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: true,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -5.3, deltaY: -4.9, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
@@ -1360,34 +1360,34 @@ function testContinuousTrustedEvents()
         horizontal: { expected: true,  preventDefault: false, detail: -5 },
         vertical:   { expected: true,  preventDefault: false, detail: -4 } }
     },
 
     // Simple line scroll tests.
     { description: "Simple horizontal wheel event by lines (1.0 - 1) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 1.0, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 1.0, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 1 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: gHorizontalLine },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
     { description: "Simple horizontal wheel event by lines (1.0 - 1) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 1.0, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 1.0, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 1 },
@@ -1395,34 +1395,34 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: gHorizontalLine },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
 
     { description: "Simple horizontal wheel event by lines (-1.0 - -1) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: -1.0, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: -1, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: -1, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -1.0, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -1 },
         vertical:   { expected: false, preventDefault: false, detail:  0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -gHorizontalLine },
         vertical:   { expected: false, preventDefault: false, detail:  0 } }
     },
     { description: "Simple horizontal wheel event by lines (-1.0 - -1) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: -1.0, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: -1, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: -1, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -1.0, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -1 },
@@ -1430,34 +1430,34 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -gHorizontalLine },
         vertical:   { expected: false, preventDefault: false, detail:  0 } }
     },
 
     { description: "Simple vertical wheel event by lines (-1.0 - -1) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 0.0, deltaY: -1.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: -1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: -1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: -1.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail:  0 },
         vertical:   { expected: true,  preventDefault: false, detail: -1 } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail:  0 },
         vertical:   { expected: true,  preventDefault: false, detail: -gLineHeight } }
     },
     { description: "Simple vertical wheel event by lines (-1.0 - -1) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 0.0, deltaY: -1.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: -1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: -1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: -1.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail:  0 },
@@ -1465,34 +1465,34 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail:  0 },
         vertical:   { expected: true,  preventDefault: false, detail: -gLineHeight } }
     },
 
     { description: "Simple vertical wheel event by lines (1.0 - 1) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 0.0, deltaY: 1.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: 1.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: 1 } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: gLineHeight } }
     },
     { description: "Simple vertical wheel event by lines (1.0 - 1) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 0.0, deltaY: 1.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: 1.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
@@ -1501,51 +1501,51 @@ function testContinuousTrustedEvents()
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: gLineHeight } }
     },
 
     // high resolution line scroll
     { description: "High resolution horizontal wheel event by lines (0.333... - 0) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 1.0 / 3, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 1.0 / 3, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: Math.floor(gHorizontalLine / 3) },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
     { description: "High resolution horizontal wheel event by lines (0.333... - 0) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 1.0 / 3, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 1.0 / 3, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: Math.floor(gHorizontalLine / 3) },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
     { description: "High resolution horizontal wheel event by lines (0.333... - 1) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 1.0 / 3, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 1.0 / 3, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 1 },
@@ -1553,51 +1553,51 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: Math.floor(gHorizontalLine / 3) },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
 
     { description: "High resolution horizontal wheel event by lines (-0.333... - 0) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: -1.0 / 3, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -1.0 / 3, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail:  0 },
         vertical:   { expected: false, preventDefault: false, detail:  0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -Math.floor(gHorizontalLine / 3) },
         vertical:   { expected: false, preventDefault: false, detail:  0 } }
     },
     { description: "High resolution horizontal wheel event by lines (-0.333... - 0) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: -1.0 / 3, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -1.0 / 3, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail:  0 },
         vertical:   { expected: false, preventDefault: false, detail:  0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -Math.floor(gHorizontalLine / 3) },
         vertical:   { expected: false, preventDefault: false, detail:  0 } }
     },
     { description: "High resolution horizontal wheel event by lines (-0.333... - -1) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: -1.0 / 3, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: -1, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: -1, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -1.0 / 3, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -1 },
@@ -1605,51 +1605,51 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -Math.floor(gHorizontalLine / 3) },
         vertical:   { expected: false, preventDefault: false, detail:  0 } }
     },
 
     { description: "High resolution vertical wheel event by lines (0.333... - 0) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 0.0, deltaY: 1.0 / 3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: 1.0 / 3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: Math.floor(gLineHeight / 3) } }
     },
     { description: "High resolution vertical wheel event by lines (0.333... - 0) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 0.0, deltaY: 1.0 / 3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: 1.0 / 3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: Math.floor(gLineHeight / 3) } }
     },
     { description: "High resolution vertical wheel event by lines (0.333... - 1) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 0.0, deltaY: 1.0 / 3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: 1.0 / 3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
@@ -1657,51 +1657,51 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: Math.floor(gLineHeight / 3) } }
     },
 
     { description: "High resolution vertical wheel event by lines (-0.333... - 0) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 0.0, deltaY: -1.0 / 3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: -1.0 / 3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail:  0 },
         vertical:   { expected: false, preventDefault: false, detail:  0 } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail:  0 },
         vertical:   { expected: true,  preventDefault: false, detail: -Math.floor(gLineHeight / 3) } }
     },
     { description: "High resolution vertical wheel event by lines (-0.333... - 0) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 0.0, deltaY: -1.0 / 3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: -1.0 / 3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail:  0 },
         vertical:   { expected: false, preventDefault: false, detail:  0 } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail:  0 },
         vertical:   { expected: true,  preventDefault: false, detail: -Math.floor(gLineHeight / 3) } }
     },
     { description: "High resolution vertical wheel event by lines (-0.333... - -1) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 0.0, deltaY: -1.0 / 3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: -1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: -1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: -1.0 / 3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail:  0 },
@@ -1710,17 +1710,17 @@ function testContinuousTrustedEvents()
         horizontal: { expected: false, preventDefault: false, detail:  0 },
         vertical:   { expected: true,  preventDefault: false, detail: -Math.floor(gLineHeight / 3) } }
     },
 
     // Oblique line scroll
     { description: "Oblique wheel event by lines (-1.0/2.0 - -1/2)",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: -1.0, deltaY: 2.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: -1, lineOrPageDeltaY: 2, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: -1, lineOrPageDeltaY: 2, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -1.0, deltaY: 2.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -1 },
@@ -1728,17 +1728,17 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -gHorizontalLine },
         vertical:   { expected: true,  preventDefault: false, detail:  gLineHeight * 2 } }
     },
 
     { description: "Oblique wheel event by lines (1.0/-2.0 - 1/-2)",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 1.0, deltaY: -2.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: -2, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: -2, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 1.0, deltaY: -2.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail:  1 },
@@ -1746,51 +1746,51 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail:  gHorizontalLine },
         vertical:   { expected: true,  preventDefault: false, detail: -gLineHeight * 2 } }
     },
 
     { description: "High resolution oblique wheel event by lines (0.5/0.333.../-0.8 - 0/0) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 0.5, deltaY: 1.0 / 3, deltaZ: -0.8, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.5, deltaY: 1.0 / 3, deltaZ: -0.8
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: Math.floor(gHorizontalLine / 2) },
         vertical:   { expected: true,  preventDefault: false, detail: Math.floor(gLineHeight / 3) } }
     },
     { description: "High resolution oblique wheel event by lines (0.5/0.333.../-0.8 - 1/0) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 0.5, deltaY: 1.0 / 3, deltaZ: -0.8, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.5, deltaY: 1.0 / 3, deltaZ: -0.8
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 1 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: Math.floor(gHorizontalLine / 2) },
         vertical:   { expected: true,  preventDefault: false, detail: Math.floor(gLineHeight / 3) } }
     },
     { description: "High resolution oblique wheel event by lines (0.5/0.333.../-0.8 - 0/1) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 0.5, deltaY: 1.0 / 3, deltaZ: -0.8, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.5, deltaY: 1.0 / 3, deltaZ: -0.8
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
@@ -1799,34 +1799,34 @@ function testContinuousTrustedEvents()
         horizontal: { expected: true,  preventDefault: false, detail: Math.floor(gHorizontalLine / 2) },
         vertical:   { expected: true,  preventDefault: false, detail: Math.floor(gLineHeight / 3) } }
     },
 
     // Simple page scroll tests.
     { description: "Simple horizontal wheel event by pages (1.0 - 1) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 1.0, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 1.0, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: UIEvent.SCROLL_PAGE_DOWN },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: gPageWidth },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
     { description: "Simple horizontal wheel event by pages (1.0 - 1) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 1.0, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 1.0, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: UIEvent.SCROLL_PAGE_DOWN },
@@ -1834,34 +1834,34 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: gPageWidth },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
 
     { description: "Simple horizontal wheel event by pages (-1.0 - -1) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: -1.0, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: -1, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: -1, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -1.0, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail:  UIEvent.SCROLL_PAGE_UP },
         vertical:   { expected: false, preventDefault: false, detail:  0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -gPageWidth },
         vertical:   { expected: false, preventDefault: false, detail:  0 } }
     },
     { description: "Simple horizontal wheel event by pages (-1.0 - -1) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: -1.0, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: -1, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: -1, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -1.0, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail:  UIEvent.SCROLL_PAGE_UP },
@@ -1869,34 +1869,34 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -gPageWidth },
         vertical:   { expected: false, preventDefault: false, detail:  0 } }
     },
 
     { description: "Simple vertical wheel event by pages (-1.0 - -1) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 0.0, deltaY: -1.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: -1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: -1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: -1.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail:  0 },
         vertical:   { expected: true,  preventDefault: false, detail:  UIEvent.SCROLL_PAGE_UP } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail:  0 },
         vertical:   { expected: true,  preventDefault: false, detail: -gPageHeight } }
     },
     { description: "Simple vertical wheel event by pages (-1.0 - -1) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 0.0, deltaY: -1.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: -1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: -1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: -1.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail:  0 },
@@ -1904,34 +1904,34 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail:  0 },
         vertical:   { expected: true,  preventDefault: false, detail: -gPageHeight } }
     },
 
     { description: "Simple vertical wheel event by pages (1.0 - 1) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 0.0, deltaY: 1.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: 1.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: UIEvent.SCROLL_PAGE_DOWN } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: gPageHeight } }
     },
     { description: "Simple vertical wheel event by pages (1.0 - 1) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 0.0, deltaY: 1.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: 1.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
@@ -1940,51 +1940,51 @@ function testContinuousTrustedEvents()
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: gPageHeight } }
     },
 
     // high resolution page scroll
     { description: "High resolution horizontal wheel event by pages (0.333... - 0) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 1.0 / 3, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 1.0 / 3, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: Math.floor(gPageWidth / 3) },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
     { description: "High resolution horizontal wheel event by pages (0.333... - 0) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 1.0 / 3, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 1.0 / 3, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: Math.floor(gPageWidth / 3) },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
     { description: "High resolution horizontal wheel event by pages (0.333... - 1) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 1.0 / 3, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 1.0 / 3, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: UIEvent.SCROLL_PAGE_DOWN },
@@ -1992,51 +1992,51 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: Math.floor(gPageWidth / 3) },
         vertical:   { expected: false, preventDefault: false, detail: 0 } }
     },
 
     { description: "High resolution horizontal wheel event by pages (-0.333... - 0) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: -1.0 / 3, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -1.0 / 3, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail:  0 },
         vertical:   { expected: false, preventDefault: false, detail:  0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -Math.floor(gPageWidth / 3) },
         vertical:   { expected: false, preventDefault: false, detail:  0 } }
     },
     { description: "High resolution horizontal wheel event by pages (-0.333... - 0) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: -1.0 / 3, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -1.0 / 3, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail:  0 },
         vertical:   { expected: false, preventDefault: false, detail:  0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -Math.floor(gPageWidth / 3) },
         vertical:   { expected: false, preventDefault: false, detail:  0 } }
     },
     { description: "High resolution horizontal wheel event by pages (-0.333... - -1) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: -1.0 / 3, deltaY: 0.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: -1, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: -1, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -1.0 / 3, deltaY: 0.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail:  UIEvent.SCROLL_PAGE_UP },
@@ -2044,51 +2044,51 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -Math.floor(gPageWidth / 3) },
         vertical:   { expected: false, preventDefault: false, detail:  0 } }
     },
 
     { description: "High resolution vertical wheel event by pages (0.333... - 0) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 0.0, deltaY: 1.0 / 3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: 1.0 / 3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: Math.floor(gPageHeight / 3) } }
     },
     { description: "High resolution vertical wheel event by pages (0.333... - 0) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 0.0, deltaY: 1.0 / 3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: 1.0 / 3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: Math.floor(gPageHeight / 3) } }
     },
     { description: "High resolution vertical wheel event by pages (0.333... - 1) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 0.0, deltaY: 1.0 / 3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: 1.0 / 3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
@@ -2096,51 +2096,51 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: Math.floor(gPageHeight / 3) } }
     },
 
     { description: "High resolution vertical wheel event by pages (-0.333... - 0) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 0.0, deltaY: -1.0 / 3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: -1.0 / 3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail:  0 },
         vertical:   { expected: false, preventDefault: false, detail:  0 } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail:  0 },
         vertical:   { expected: true,  preventDefault: false, detail: -Math.floor(gPageHeight / 3) } }
     },
     { description: "High resolution vertical wheel event by pages (-0.333... - 0) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 0.0, deltaY: -1.0 / 3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: -1.0 / 3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail:  0 },
         vertical:   { expected: false, preventDefault: false, detail:  0 } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail:  0 },
         vertical:   { expected: true,  preventDefault: false, detail: -Math.floor(gPageHeight / 3) } }
     },
     { description: "High resolution vertical wheel event by pages (-0.333... - -1) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 0.0, deltaY: -1.0 / 3, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: -1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: -1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.0, deltaY: -1.0 / 3, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail:  0 },
@@ -2149,17 +2149,17 @@ function testContinuousTrustedEvents()
         horizontal: { expected: false, preventDefault: false, detail:  0 },
         vertical:   { expected: true,  preventDefault: false, detail: -Math.floor(gPageHeight / 3) } }
     },
 
     // Oblique page scroll
     { description: "Oblique wheel event by pages (-1.0/2.0 - -1/2)",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: -1.0, deltaY: 2.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: -1, lineOrPageDeltaY: 2, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: -1, lineOrPageDeltaY: 2, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -1.0, deltaY: 2.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail:  UIEvent.SCROLL_PAGE_UP },
@@ -2167,17 +2167,17 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -gPageWidth },
         vertical:   { expected: true,  preventDefault: false, detail:  gPageHeight * 2 } }
     },
 
     { description: "Oblique wheel event by pages (1.0/-2.0 - 1/-2)",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 1.0, deltaY: -2.0, deltaZ: 0.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: -2, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: -2, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 1.0, deltaY: -2.0, deltaZ: 0.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail:  UIEvent.SCROLL_PAGE_DOWN },
@@ -2185,51 +2185,51 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail:  gPageWidth },
         vertical:   { expected: true,  preventDefault: false, detail: -gPageHeight * 2 } }
     },
 
     { description: "High resolution oblique wheel event by pages (0.5/0.333.../-0.8 - 0/0) #1",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 0.5, deltaY: 1.0 / 3, deltaZ: -0.8, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.5, deltaY: 1.0 / 3, deltaZ: -0.8
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: Math.floor(gPageWidth / 2) },
         vertical:   { expected: true,  preventDefault: false, detail: Math.floor(gPageHeight / 3) } }
     },
     { description: "High resolution oblique wheel event by pages (0.5/0.333.../-0.8 - 1/0) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 0.5, deltaY: 1.0 / 3, deltaZ: -0.8, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 0, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 0, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.5, deltaY: 1.0 / 3, deltaZ: -0.8
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: UIEvent.SCROLL_PAGE_DOWN },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: Math.floor(gPageWidth / 2) },
         vertical:   { expected: true,  preventDefault: false, detail: Math.floor(gPageHeight / 3) } }
     },
     { description: "High resolution oblique wheel event by pages (0.5/0.333.../-0.8 - 0/1) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 0.5, deltaY: 1.0 / 3, deltaZ: -0.8, isMomentum: false,
-               lineOrPageDeltaX: 0, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 0, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.5, deltaY: 1.0 / 3, deltaZ: -0.8
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
@@ -2238,51 +2238,51 @@ function testContinuousTrustedEvents()
         horizontal: { expected: true,  preventDefault: false, detail: Math.floor(gPageWidth / 2) },
         vertical:   { expected: true,  preventDefault: false, detail: Math.floor(gPageHeight / 3) } }
     },
 
     // preventDefault() shouldn't prevent other legacy events.
     { description: "preventDefault() shouldn't prevent other legacy events (pixel)",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 16.0, deltaY: 16.0, deltaZ: 16.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 16.0, deltaY: 16.0, deltaZ: 16.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: true, detail: 1 },
         vertical:   { expected: true,  preventDefault: true, detail: 1 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: true, detail: 16 },
         vertical:   { expected: true,  preventDefault: true, detail: 16 } },
     },
     { description: "preventDefault() shouldn't prevent other legacy events (line)",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: true, detail: 1 },
         vertical:   { expected: true,  preventDefault: true, detail: 1 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: true, detail: gHorizontalLine },
         vertical:   { expected: true,  preventDefault: true, detail: gLineHeight } },
     },
     { description: "preventDefault() shouldn't prevent other legacy events (page)",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: true, detail: UIEvent.SCROLL_PAGE_DOWN },
@@ -2291,51 +2291,51 @@ function testContinuousTrustedEvents()
         horizontal: { expected: true,  preventDefault: true, detail: gPageWidth },
         vertical:   { expected: true,  preventDefault: true, detail: gPageHeight } },
     },
 
     // If wheel event is consumed by preventDefault(), legacy events are not necessary.
     { description: "If wheel event is consumed by preventDefault(), legacy events are not necessary (pixel)",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 16.0, deltaY: 16.0, deltaZ: 16.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: true,
         deltaX: 16.0, deltaY: 16.0, deltaZ: 16.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
     },
     { description: "If wheel event is consumed by preventDefault(), legacy events are not necessary (line)",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: true,
         deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
     },
     { description: "If wheel event is consumed by preventDefault(), legacy events are not necessary (page)",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: true,
         deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
@@ -2344,51 +2344,51 @@ function testContinuousTrustedEvents()
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
     },
 
     // modifier key state tests
     { description: "modifier key tests (shift, pixel)",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 16.0, deltaY: 16.0, deltaZ: 16.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: true, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 16.0, deltaY: 16.0, deltaZ: 16.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 1 },
         vertical:   { expected: true,  preventDefault: false, detail: 1 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: true,  detail: 16 },
         vertical:   { expected: true,  preventDefault: true,  detail: 16 } },
     },
     { description: "modifier key tests (shift, line)",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: true, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 1 },
         vertical:   { expected: true,  preventDefault: false, detail: 1 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: true,  detail: gHorizontalLine },
         vertical:   { expected: true,  preventDefault: true,  detail: gLineHeight } },
     },
     { description: "modifier key tests (shift, page)",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: true, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: UIEvent.SCROLL_PAGE_DOWN },
@@ -2396,51 +2396,51 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: true,  detail: gPageWidth },
         vertical:   { expected: true,  preventDefault: true,  detail: gPageHeight } },
     },
 
     { description: "modifier key tests (ctrl, pixel)",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 16.0, deltaY: 16.0, deltaZ: 16.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: true, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 16.0, deltaY: 16.0, deltaZ: 16.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 1 },
         vertical:   { expected: true,  preventDefault: false, detail: 1 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: true,  detail: 16 },
         vertical:   { expected: true,  preventDefault: true,  detail: 16 } },
     },
     { description: "modifier key tests (ctrl, line)",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: true, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 1 },
         vertical:   { expected: true,  preventDefault: false, detail: 1 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: true,  detail: gHorizontalLine },
         vertical:   { expected: true,  preventDefault: true,  detail: gLineHeight } },
     },
     { description: "modifier key tests (ctrl, page)",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: true, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: UIEvent.SCROLL_PAGE_DOWN },
@@ -2448,51 +2448,51 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: true,  detail: gPageWidth },
         vertical:   { expected: true,  preventDefault: true,  detail: gPageHeight } },
     },
 
     { description: "modifier key tests (alt, pixel)",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 16.0, deltaY: 16.0, deltaZ: 16.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: true, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 16.0, deltaY: 16.0, deltaZ: 16.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 1 },
         vertical:   { expected: true,  preventDefault: false, detail: 1 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: true,  detail: 16 },
         vertical:   { expected: true,  preventDefault: true,  detail: 16 } },
     },
     { description: "modifier key tests (alt, line)",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: true, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 1 },
         vertical:   { expected: true,  preventDefault: false, detail: 1 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: true,  detail: gHorizontalLine },
         vertical:   { expected: true,  preventDefault: true,  detail: gLineHeight } },
     },
     { description: "modifier key tests (alt, page)",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: true, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: UIEvent.SCROLL_PAGE_DOWN },
@@ -2500,51 +2500,51 @@ function testContinuousTrustedEvents()
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: true,  detail: gPageWidth },
         vertical:   { expected: true,  preventDefault: true,  detail: gPageHeight } },
     },
 
     { description: "modifier key tests (meta, pixel)",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 16.0, deltaY: 16.0, deltaZ: 16.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: true },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 16.0, deltaY: 16.0, deltaZ: 16.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 1 },
         vertical:   { expected: true,  preventDefault: false, detail: 1 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: true,  detail: 16 },
         vertical:   { expected: true,  preventDefault: true,  detail: 16 } },
     },
     { description: "modifier key tests (meta, line)",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: true },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 1 },
         vertical:   { expected: true,  preventDefault: false, detail: 1 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: true,  detail: gHorizontalLine },
         vertical:   { expected: true,  preventDefault: true,  detail: gLineHeight } },
     },
     { description: "modifier key tests (meta, page)",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0, isMomentum: true,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: UIEvent.SCROLL_PAGE_DOWN },
@@ -2553,102 +2553,102 @@ function testContinuousTrustedEvents()
         horizontal: { expected: true,  preventDefault: true,  detail: gPageWidth },
         vertical:   { expected: true,  preventDefault: true,  detail: gPageHeight } },
     },
 
     // Momentum scroll should cause legacy events.
     { description: "Momentum scroll should cause legacy events (pixel, not momentum)",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 16.0, deltaY: 16.0, deltaZ: 16.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 16.0, deltaY: 16.0, deltaZ: 16.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 1 },
         vertical:   { expected: true,  preventDefault: false, detail: 1 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 16 },
         vertical:   { expected: true,  preventDefault: false, detail: 16 } },
     },
     { description: "Momentum scroll should cause legacy events (pixel, momentum)",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: 16.0, deltaY: 16.0, deltaZ: 16.0, isMomentum: true,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 16.0, deltaY: 16.0, deltaZ: 16.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 1 },
         vertical:   { expected: true,  preventDefault: false, detail: 1 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 16 },
         vertical:   { expected: true,  preventDefault: false, detail: 16 } },
     },
     { description: "Momentum scroll should cause legacy events (line, not momentum)",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 1 },
         vertical:   { expected: true,  preventDefault: false, detail: 1 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: gHorizontalLine },
         vertical:   { expected: true,  preventDefault: false, detail: gLineHeight } },
     },
     { description: "Momentum scroll should cause legacy events (line, momentum)",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0, isMomentum: true,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 1 },
         vertical:   { expected: true,  preventDefault: false, detail: 1 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: gHorizontalLine },
         vertical:   { expected: true,  preventDefault: false, detail: gLineHeight } },
     },
     { description: "Momentum scroll should cause legacy events (page, not momentum)",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0, isMomentum: false,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: UIEvent.SCROLL_PAGE_DOWN },
         vertical:   { expected: true,  preventDefault: false, detail: UIEvent.SCROLL_PAGE_DOWN } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: gPageWidth },
         vertical:   { expected: true,  preventDefault: false, detail: gPageHeight } },
     },
     { description: "Momentum scroll should cause legacy events (page, momentum)",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0, isMomentum: true,
-               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 1, lineOrPageDeltaY: 1, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 1.0, deltaY: 1.0, deltaZ: 1.0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: UIEvent.SCROLL_PAGE_DOWN },
@@ -2661,51 +2661,51 @@ function testContinuousTrustedEvents()
     // Tests for accumulation delta when delta_multiplier_is customized.
     { description: "lineOrPageDelta should be recomputed by ESM (pixel) #1",
       prepare: function () {
         SpecialPowers.setIntPref("mousewheel.default.delta_multiplier_x", 200);
         SpecialPowers.setIntPref("mousewheel.default.delta_multiplier_y", 300);
       },
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: gHorizontalLine / 4, deltaY: gLineHeight / 8, deltaZ: 0,
-               lineOrPageDeltaX: 3, lineOrPageDeltaY: 5, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 3, lineOrPageDeltaY: 5, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: gHorizontalLine / 4 * 2, deltaY: gLineHeight / 8 * 3, deltaZ: 0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: Math.floor(gHorizontalLine / 4 * 2) },
         vertical:   { expected: true,  preventDefault: false, detail: Math.floor(gLineHeight / 8 * 3) } },
     },
     { description: "lineOrPageDelta should be recomputed by ESM (pixel) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: gHorizontalLine / 4 + 1, deltaY: gLineHeight / 8 + 1, deltaZ: 0,
-               lineOrPageDeltaX: 3, lineOrPageDeltaY: 5, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 3, lineOrPageDeltaY: 5, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: (gHorizontalLine / 4 + 1) * 2, deltaY: (gLineHeight / 8 + 1) * 3, deltaZ: 0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 1 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,   preventDefault: false, detail: Math.floor((gHorizontalLine / 4 + 1) * 2) },
         vertical:   { expected: true,   preventDefault: false, detail: Math.floor((gLineHeight / 8 + 1) * 3) } },
     },
     { description: "lineOrPageDelta should be recomputed by ESM (pixel) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: gHorizontalLine / 4 + 1, deltaY: gLineHeight / 8 + 1, deltaZ: 0,
-               lineOrPageDeltaX: 3, lineOrPageDeltaY: 5, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 3, lineOrPageDeltaY: 5, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: (gHorizontalLine / 4 + 1) * 2, deltaY: (gLineHeight / 8 + 1) * 3, deltaZ: 0
       },
       DOMMouseScroll: {
         horizontal: { expected: false,  preventDefault: false, detail: 0 },
@@ -2721,51 +2721,51 @@ function testContinuousTrustedEvents()
 
     { description: "lineOrPageDelta should be recomputed by ESM (pixel, negative, shift) #1",
       prepare: function () {
         SpecialPowers.setIntPref("mousewheel.with_shift.delta_multiplier_x", 200);
         SpecialPowers.setIntPref("mousewheel.with_shift.delta_multiplier_y", 300);
       },
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: -gHorizontalLine / 4, deltaY: -gLineHeight / 8, deltaZ: 0,
-               lineOrPageDeltaX: -3, lineOrPageDeltaY: -5, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: -3, lineOrPageDeltaY: -5, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: true, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -gHorizontalLine / 4 * 2, deltaY: -gLineHeight / 8 * 3, deltaZ: 0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: Math.ceil(-gHorizontalLine / 4 * 2) },
         vertical:   { expected: true,  preventDefault: false, detail: Math.ceil(-gLineHeight / 8 * 3) } },
     },
     { description: "lineOrPageDelta should be recomputed by ESM (pixel, negative, shift) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: -(gHorizontalLine / 4 + 1), deltaY: -(gLineHeight / 8 + 1), deltaZ: 0,
-               lineOrPageDeltaX: -3, lineOrPageDeltaY: -5, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: -3, lineOrPageDeltaY: -5, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: true, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -(gHorizontalLine / 4 + 1) * 2, deltaY: -(gLineHeight / 8 + 1) * 3, deltaZ: 0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -1 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: Math.ceil(-(gHorizontalLine / 4 + 1) * 2) },
         vertical:   { expected: true,  preventDefault: false, detail: Math.ceil(-(gLineHeight / 8 + 1) * 3) } },
     },
     { description: "lineOrPageDelta should be recomputed by ESM (pixel, negative, shift) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_PIXEL,
                deltaX: -(gHorizontalLine / 4 + 1), deltaY: -(gLineHeight / 8 + 1), deltaZ: 0,
-               lineOrPageDeltaX: 3, lineOrPageDeltaY: 5, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 3, lineOrPageDeltaY: 5, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: true, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -(gHorizontalLine / 4 + 1) * 2, deltaY: -(gLineHeight / 8 + 1) * 3, deltaZ: 0
       },
       DOMMouseScroll: {
         horizontal: { expected: false,  preventDefault: false, detail: 0 },
@@ -2781,51 +2781,51 @@ function testContinuousTrustedEvents()
 
     { description: "lineOrPageDelta should be recomputed by ESM (line) #1",
       prepare: function () {
         SpecialPowers.setIntPref("mousewheel.default.delta_multiplier_x", 200);
         SpecialPowers.setIntPref("mousewheel.default.delta_multiplier_y", 100);
       },
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 0.3, deltaY: 0.4, deltaZ: 0,
-               lineOrPageDeltaX: 3, lineOrPageDeltaY: 5, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 3, lineOrPageDeltaY: 5, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.6, deltaY: 0.4, deltaZ: 0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: Math.floor(gHorizontalLine * 0.6) },
         vertical:   { expected: true,  preventDefault: false, detail: Math.floor(gLineHeight * 0.4) } },
     },
     { description: "lineOrPageDelta should be recomputed by ESM (line) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 0.3, deltaY: 0.4, deltaZ: 0,
-               lineOrPageDeltaX: 3, lineOrPageDeltaY: 5, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 3, lineOrPageDeltaY: 5, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.6, deltaY: 0.4, deltaZ: 0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: 1 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: Math.floor(gHorizontalLine * 0.6) },
         vertical:   { expected: true,  preventDefault: false, detail: Math.floor(gLineHeight * 0.4) } },
     },
     { description: "lineOrPageDelta should be recomputed by ESM (line) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: 0.3, deltaY: 0.4, deltaZ: 0,
-               lineOrPageDeltaX: 3, lineOrPageDeltaY: 5, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 3, lineOrPageDeltaY: 5, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.6, deltaY: 0.4, deltaZ: 0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
@@ -2841,51 +2841,51 @@ function testContinuousTrustedEvents()
 
     { description: "lineOrPageDelta should be recomputed by ESM (line, negative) #1",
       prepare: function () {
         SpecialPowers.setIntPref("mousewheel.default.delta_multiplier_x", 200);
         SpecialPowers.setIntPref("mousewheel.default.delta_multiplier_y", -100);
       },
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: -0.3, deltaY: -0.4, deltaZ: 0,
-               lineOrPageDeltaX: -3, lineOrPageDeltaY: -5, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: -3, lineOrPageDeltaY: -5, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -0.6, deltaY: 0.4, deltaZ: 0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: Math.ceil(gHorizontalLine * -0.6) },
         vertical:   { expected: true,  preventDefault: false, detail: Math.floor(gLineHeight * 0.4) } },
     },
     { description: "lineOrPageDelta should be recomputed by ESM (line, negative) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: -0.3, deltaY: -0.4, deltaZ: 0,
-               lineOrPageDeltaX: -3, lineOrPageDeltaY: -5, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: -3, lineOrPageDeltaY: -5, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -0.6, deltaY: 0.4, deltaZ: 0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: -1 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: Math.ceil(gHorizontalLine * -0.6) },
         vertical:   { expected: true,  preventDefault: false, detail: Math.floor(gLineHeight * 0.4) } },
     },
     { description: "lineOrPageDelta should be recomputed by ESM (line, negative) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_LINE,
                deltaX: -0.3, deltaY: -0.4, deltaZ: 0,
-               lineOrPageDeltaX: -3, lineOrPageDeltaY: -5, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: -3, lineOrPageDeltaY: -5, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -0.6, deltaY: 0.4, deltaZ: 0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
@@ -2901,51 +2901,51 @@ function testContinuousTrustedEvents()
 
     { description: "lineOrPageDelta should be recomputed by ESM (page) #1",
       prepare: function () {
         SpecialPowers.setIntPref("mousewheel.default.delta_multiplier_x", 100);
         SpecialPowers.setIntPref("mousewheel.default.delta_multiplier_y", 200);
       },
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 0.3, deltaY: 0.4, deltaZ: 0,
-               lineOrPageDeltaX: 3, lineOrPageDeltaY: 5, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 3, lineOrPageDeltaY: 5, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.3, deltaY: 0.8, deltaZ: 0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: Math.floor(gPageWidth * 0.3) },
         vertical:   { expected: true,  preventDefault: false, detail: Math.floor(gPageHeight * 0.8) } },
     },
     { description: "lineOrPageDelta should be recomputed by ESM (page) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 0.3, deltaY: 0.4, deltaZ: 0,
-               lineOrPageDeltaX: 3, lineOrPageDeltaY: 5, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 3, lineOrPageDeltaY: 5, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.3, deltaY: 0.8, deltaZ: 0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: UIEvent.SCROLL_PAGE_DOWN } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: Math.floor(gPageWidth * 0.3) },
         vertical:   { expected: true,  preventDefault: false, detail: Math.floor(gPageHeight * 0.8) } },
     },
     { description: "lineOrPageDelta should be recomputed by ESM (page) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: 0.4, deltaY: 0.4, deltaZ: 0,
-               lineOrPageDeltaX: 3, lineOrPageDeltaY: 5, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: 3, lineOrPageDeltaY: 5, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: 0.4, deltaY: 0.8, deltaZ: 0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: UIEvent.SCROLL_PAGE_DOWN },
@@ -2961,51 +2961,51 @@ function testContinuousTrustedEvents()
 
     { description: "lineOrPageDelta should be recomputed by ESM (page, negative) #1",
       prepare: function () {
         SpecialPowers.setIntPref("mousewheel.default.delta_multiplier_x", 100);
         SpecialPowers.setIntPref("mousewheel.default.delta_multiplier_y", 200);
       },
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: -0.3, deltaY: -0.4, deltaZ: 0,
-               lineOrPageDeltaX: -3, lineOrPageDeltaY: -5, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: -3, lineOrPageDeltaY: -5, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -0.3, deltaY: -0.8, deltaZ: 0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: false, preventDefault: false, detail: 0 } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: Math.ceil(gPageWidth * -0.3) },
         vertical:   { expected: true,  preventDefault: false, detail: Math.ceil(gPageHeight * -0.8) } },
     },
     { description: "lineOrPageDelta should be recomputed by ESM (page, negative) #2",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: -0.3, deltaY: -0.4, deltaZ: 0,
-               lineOrPageDeltaX: -3, lineOrPageDeltaY: -5, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: -3, lineOrPageDeltaY: -5, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -0.3, deltaY: -0.8, deltaZ: 0
       },
       DOMMouseScroll: {
         horizontal: { expected: false, preventDefault: false, detail: 0 },
         vertical:   { expected: true,  preventDefault: false, detail: UIEvent.SCROLL_PAGE_UP } },
       MozMousePixelScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: Math.ceil(gPageWidth * -0.3) },
         vertical:   { expected: true,  preventDefault: false, detail: Math.ceil(gPageHeight * -0.8) } },
     },
     { description: "lineOrPageDelta should be recomputed by ESM (page, negative) #3",
       event: { deltaMode: WheelEvent.DOM_DELTA_PAGE,
                deltaX: -0.4, deltaY: -0.4, deltaZ: 0,
-               lineOrPageDeltaX: -3, lineOrPageDeltaY: -5, isPixelOnlyDevice: false,
+               lineOrPageDeltaX: -3, lineOrPageDeltaY: -5, isNoLineOrPageDelta: false,
                isCustomizedByPrefs: false,
                shiftKey: false, ctrlKey: false, altKey: false, metaKey: false },
       wheel: {
         expected: true, preventDefault: false,
         deltaX: -0.4, deltaY: -0.8, deltaZ: 0
       },
       DOMMouseScroll: {
         horizontal: { expected: true,  preventDefault: false, detail: UIEvent.SCROLL_PAGE_UP },
--- a/dom/interfaces/base/nsIDOMWindowUtils.idl
+++ b/dom/interfaces/base/nsIDOMWindowUtils.idl
@@ -43,17 +43,17 @@ interface nsIDOMFile;
 interface nsIFile;
 interface nsIDOMClientRect;
 interface nsIURI;
 interface nsIDOMEventTarget;
 interface nsIRunnable;
 interface nsICompositionStringSynthesizer;
 interface nsITranslationNodeList;
 
-[scriptable, uuid(6f10cbf8-bd4e-4c56-8a5a-35641efcf286)]
+[scriptable, uuid(46e3f206-9a8f-4d66-8248-7ec6a37de45a)]
 interface nsIDOMWindowUtils : nsISupports {
 
   /**
    * Image animation mode of the window. When this attribute's value
    * is changed, the implementation should set all images in the window
    * to the given value. That is, when set to kDontAnimMode, all images
    * will stop animating. The attribute's value must be one of the
    * animationMode values from imgIContainer.
@@ -463,19 +463,21 @@ interface nsIDOMWindowUtils : nsISupport
    *                           dispatch NS_MOUSE_SCROLL event for horizontal
    *                           scroll.
    * @param aLineOrPageDeltaY  If you set this value non-zero for
    *                           DOM_DELTA_PIXEL event, EventStateManager will
    *                           dispatch NS_MOUSE_SCROLL event for vertical
    *                           scroll.
    * @param aOptions           Set following flags.
    */
-   const unsigned long WHEEL_EVENT_CAUSED_BY_PIXEL_ONLY_DEVICE = 0x0001;
-   const unsigned long WHEEL_EVENT_CAUSED_BY_MOMENTUM          = 0x0002;
-   const unsigned long WHEEL_EVENT_CUSTOMIZED_BY_USER_PREFS    = 0x0004;
+   const unsigned long WHEEL_EVENT_CAUSED_BY_NO_LINE_OR_PAGE_DELTA_DEVICE = 0x0001;
+   // @deprecated Use WHEEL_EVENT_CAUSED_BY_NO_LINE_OR_PAGE_DELTA_DEVICE.
+   const unsigned long WHEEL_EVENT_CAUSED_BY_PIXEL_ONLY_DEVICE            = 0x0001;
+   const unsigned long WHEEL_EVENT_CAUSED_BY_MOMENTUM          	          = 0x0002;
+   const unsigned long WHEEL_EVENT_CUSTOMIZED_BY_USER_PREFS               = 0x0004;
    // If any of the following flags is specified this method will throw an
    // exception in case the relevant overflowDelta has an unexpected value.
    const unsigned long WHEEL_EVENT_EXPECTED_OVERFLOW_DELTA_X_ZERO      = 0x0010;
    const unsigned long WHEEL_EVENT_EXPECTED_OVERFLOW_DELTA_X_POSITIVE  = 0x0020;
    const unsigned long WHEEL_EVENT_EXPECTED_OVERFLOW_DELTA_X_NEGATIVE  = 0x0040;
    const unsigned long WHEEL_EVENT_EXPECTED_OVERFLOW_DELTA_Y_ZERO      = 0x0100;
    const unsigned long WHEEL_EVENT_EXPECTED_OVERFLOW_DELTA_Y_POSITIVE  = 0x0200;
    const unsigned long WHEEL_EVENT_EXPECTED_OVERFLOW_DELTA_Y_NEGATIVE  = 0x0400;
--- a/services/sync/tps/extensions/mozmill/resource/stdlib/EventUtils.js
+++ b/services/sync/tps/extensions/mozmill/resource/stdlib/EventUtils.js
@@ -312,18 +312,19 @@ function synthesizeTouchAtCenter(aTarget
 
 /**
  * Synthesize a wheel event on a target. The actual client point is determined
  * by taking the aTarget's client box and offseting it by aOffsetX and
  * aOffsetY.
  *
  * aEvent is an object which may contain the properties:
  *   shiftKey, ctrlKey, altKey, metaKey, accessKey, deltaX, deltaY, deltaZ,
- *   deltaMode, lineOrPageDeltaX, lineOrPageDeltaY, isMomentum, isPixelOnlyDevice,
- *   isCustomizedByPrefs, expectedOverflowDeltaX, expectedOverflowDeltaY
+ *   deltaMode, lineOrPageDeltaX, lineOrPageDeltaY, isMomentum,
+ *   isNoLineOrPageDelta, isCustomizedByPrefs, expectedOverflowDeltaX,
+ *   expectedOverflowDeltaY
  *
  * deltaMode must be defined, others are ok even if undefined.
  *
  * expectedOverflowDeltaX and expectedOverflowDeltaY take integer value.  The
  * value is just checked as 0 or positive or negative.
  *
  * aWindow is optional, and defaults to the current window object.
  */
@@ -331,19 +332,18 @@ function synthesizeWheel(aTarget, aOffse
 {
   var utils = _getDOMWindowUtils(aWindow);
   if (!utils) {
     return;
   }
 
   var modifiers = _parseModifiers(aEvent);
   var options = 0;
-  if (aEvent.isPixelOnlyDevice &&
-      (aEvent.deltaMode == WheelEvent.DOM_DELTA_PIXEL)) {
-    options |= utils.WHEEL_EVENT_CAUSED_BY_PIXEL_ONLY_DEVICE;
+  if (aEvent.isNoLineOrPageDelta) {
+    options |= utils.WHEEL_EVENT_CAUSED_BY_NO_LINE_OR_PAGE_DELTA_DEVICE;
   }
   if (aEvent.isMomentum) {
     options |= utils.WHEEL_EVENT_CAUSED_BY_MOMENTUM;
   }
   if (aEvent.isCustomizedByPrefs) {
     options |= utils.WHEEL_EVENT_CUSTOMIZED_BY_USER_PREFS;
   }
   if (typeof aEvent.expectedOverflowDeltaX !== "undefined") {
@@ -359,18 +359,17 @@ function synthesizeWheel(aTarget, aOffse
     if (aEvent.expectedOverflowDeltaY === 0) {
       options |= utils.WHEEL_EVENT_EXPECTED_OVERFLOW_DELTA_Y_ZERO;
     } else if (aEvent.expectedOverflowDeltaY > 0) {
       options |= utils.WHEEL_EVENT_EXPECTED_OVERFLOW_DELTA_Y_POSITIVE;
     } else {
       options |= utils.WHEEL_EVENT_EXPECTED_OVERFLOW_DELTA_Y_NEGATIVE;
     }
   }
-  var isPixelOnlyDevice =
-    aEvent.isPixelOnlyDevice && aEvent.deltaMode == WheelEvent.DOM_DELTA_PIXEL;
+  var isNoLineOrPageDelta = aEvent.isNoLineOrPageDelta;
 
   // Avoid the JS warnings "reference to undefined property"
   if (!aEvent.deltaX) {
     aEvent.deltaX = 0;
   }
   if (!aEvent.deltaY) {
     aEvent.deltaY = 0;
   }
--- a/testing/mochitest/tests/SimpleTest/EventUtils.js
+++ b/testing/mochitest/tests/SimpleTest/EventUtils.js
@@ -337,18 +337,19 @@ function synthesizeTouchAtCenter(aTarget
 
 /**
  * Synthesize a wheel event on a target. The actual client point is determined
  * by taking the aTarget's client box and offseting it by aOffsetX and
  * aOffsetY.
  *
  * aEvent is an object which may contain the properties:
  *   shiftKey, ctrlKey, altKey, metaKey, accessKey, deltaX, deltaY, deltaZ,
- *   deltaMode, lineOrPageDeltaX, lineOrPageDeltaY, isMomentum, isPixelOnlyDevice,
- *   isCustomizedByPrefs, expectedOverflowDeltaX, expectedOverflowDeltaY
+ *   deltaMode, lineOrPageDeltaX, lineOrPageDeltaY, isMomentum,
+ *   isNoLineOrPageDelta, isCustomizedByPrefs, expectedOverflowDeltaX,
+ *   expectedOverflowDeltaY
  *
  * deltaMode must be defined, others are ok even if undefined.
  *
  * expectedOverflowDeltaX and expectedOverflowDeltaY take integer value.  The
  * value is just checked as 0 or positive or negative.
  *
  * aWindow is optional, and defaults to the current window object.
  */
@@ -356,19 +357,18 @@ function synthesizeWheel(aTarget, aOffse
 {
   var utils = _getDOMWindowUtils(aWindow);
   if (!utils) {
     return;
   }
 
   var modifiers = _parseModifiers(aEvent);
   var options = 0;
-  if (aEvent.isPixelOnlyDevice &&
-      (aEvent.deltaMode == WheelEvent.DOM_DELTA_PIXEL)) {
-    options |= utils.WHEEL_EVENT_CAUSED_BY_PIXEL_ONLY_DEVICE;
+  if (aEvent.isNoLineOrPageDelta) {
+    options |= utils.WHEEL_EVENT_CAUSED_BY_NO_LINE_OR_PAGE_DELTA_DEVICE;
   }
   if (aEvent.isMomentum) {
     options |= utils.WHEEL_EVENT_CAUSED_BY_MOMENTUM;
   }
   if (aEvent.isCustomizedByPrefs) {
     options |= utils.WHEEL_EVENT_CUSTOMIZED_BY_USER_PREFS;
   }
   if (typeof aEvent.expectedOverflowDeltaX !== "undefined") {
@@ -384,18 +384,17 @@ function synthesizeWheel(aTarget, aOffse
     if (aEvent.expectedOverflowDeltaY === 0) {
       options |= utils.WHEEL_EVENT_EXPECTED_OVERFLOW_DELTA_Y_ZERO;
     } else if (aEvent.expectedOverflowDeltaY > 0) {
       options |= utils.WHEEL_EVENT_EXPECTED_OVERFLOW_DELTA_Y_POSITIVE;
     } else {
       options |= utils.WHEEL_EVENT_EXPECTED_OVERFLOW_DELTA_Y_NEGATIVE;
     }
   }
-  var isPixelOnlyDevice =
-    aEvent.isPixelOnlyDevice && aEvent.deltaMode == WheelEvent.DOM_DELTA_PIXEL;
+  var isNoLineOrPageDelta = aEvent.isNoLineOrPageDelta;
 
   // Avoid the JS warnings "reference to undefined property"
   if (!aEvent.deltaX) {
     aEvent.deltaX = 0;
   }
   if (!aEvent.deltaY) {
     aEvent.deltaY = 0;
   }
--- a/widget/MouseEvents.h
+++ b/widget/MouseEvents.h
@@ -415,17 +415,17 @@ private:
 
 public:
   virtual WidgetWheelEvent* AsWheelEvent() MOZ_OVERRIDE { return this; }
 
   WidgetWheelEvent(bool aIsTrusted, uint32_t aMessage, nsIWidget* aWidget) :
     WidgetMouseEventBase(aIsTrusted, aMessage, aWidget, NS_WHEEL_EVENT),
     deltaX(0.0), deltaY(0.0), deltaZ(0.0),
     deltaMode(nsIDOMWheelEvent::DOM_DELTA_PIXEL),
-    customizedByUserPrefs(false), isMomentum(false), isPixelOnlyDevice(false),
+    customizedByUserPrefs(false), isMomentum(false), mIsNoLineOrPageDelta(false),
     lineOrPageDeltaX(0), lineOrPageDeltaY(0), scrollType(SCROLL_DEFAULT),
     overflowDeltaX(0.0), overflowDeltaY(0.0),
     mViewPortIsOverscrolled(false)
   {
   }
 
   virtual WidgetEvent* Duplicate() const MOZ_OVERRIDE
   {
@@ -455,19 +455,19 @@ public:
   // Otherwise, i.e., they are computed from native events, false.
   bool customizedByUserPrefs;
 
   // true if the event is caused by momentum.
   bool isMomentum;
 
   // If device event handlers don't know when they should set lineOrPageDeltaX
   // and lineOrPageDeltaY, this is true.  Otherwise, false.
-  // If isPixelOnlyDevice is true, ESM will generate NS_MOUSE_SCROLL events
-  // when accumulated pixel delta values reach a line height.
-  bool isPixelOnlyDevice;
+  // If mIsNoLineOrPageDelta is true, ESM will generate NS_MOUSE_SCROLL events
+  // when accumulated delta values reach a line height.
+  bool mIsNoLineOrPageDelta;
 
   // If widget sets lineOrPageDelta, EventStateManager will dispatch
   // NS_MOUSE_SCROLL event for compatibility.  Note that the delta value means
   // pages if the deltaMode is DOM_DELTA_PAGE, otherwise, lines.
   int32_t lineOrPageDeltaX;
   int32_t lineOrPageDeltaY;
 
   // When the default action for an wheel event is moving history or zooming,
@@ -526,17 +526,17 @@ public:
     AssignMouseEventBaseData(aEvent, aCopyTargets);
 
     deltaX = aEvent.deltaX;
     deltaY = aEvent.deltaY;
     deltaZ = aEvent.deltaZ;
     deltaMode = aEvent.deltaMode;
     customizedByUserPrefs = aEvent.customizedByUserPrefs;
     isMomentum = aEvent.isMomentum;
-    isPixelOnlyDevice = aEvent.isPixelOnlyDevice;
+    mIsNoLineOrPageDelta = aEvent.mIsNoLineOrPageDelta;
     lineOrPageDeltaX = aEvent.lineOrPageDeltaX;
     lineOrPageDeltaY = aEvent.lineOrPageDeltaY;
     scrollType = aEvent.scrollType;
     overflowDeltaX = aEvent.overflowDeltaX;
     overflowDeltaY = aEvent.overflowDeltaY;
     mViewPortIsOverscrolled = aEvent.mViewPortIsOverscrolled;
   }
 };
--- a/widget/nsGUIEventIPC.h
+++ b/widget/nsGUIEventIPC.h
@@ -136,17 +136,17 @@ struct ParamTraits<mozilla::WidgetWheelE
   {
     WriteParam(aMsg, static_cast<mozilla::WidgetMouseEventBase>(aParam));
     WriteParam(aMsg, aParam.deltaX);
     WriteParam(aMsg, aParam.deltaY);
     WriteParam(aMsg, aParam.deltaZ);
     WriteParam(aMsg, aParam.deltaMode);
     WriteParam(aMsg, aParam.customizedByUserPrefs);
     WriteParam(aMsg, aParam.isMomentum);
-    WriteParam(aMsg, aParam.isPixelOnlyDevice);
+    WriteParam(aMsg, aParam.mIsNoLineOrPageDelta);
     WriteParam(aMsg, aParam.lineOrPageDeltaX);
     WriteParam(aMsg, aParam.lineOrPageDeltaY);
     WriteParam(aMsg, static_cast<int32_t>(aParam.scrollType));
     WriteParam(aMsg, aParam.overflowDeltaX);
     WriteParam(aMsg, aParam.overflowDeltaY);
   }
 
   static bool Read(const Message* aMsg, void** aIter, paramType* aResult)
@@ -156,17 +156,17 @@ struct ParamTraits<mozilla::WidgetWheelE
       ReadParam(aMsg, aIter,
                 static_cast<mozilla::WidgetMouseEventBase*>(aResult)) &&
       ReadParam(aMsg, aIter, &aResult->deltaX) &&
       ReadParam(aMsg, aIter, &aResult->deltaY) &&
       ReadParam(aMsg, aIter, &aResult->deltaZ) &&
       ReadParam(aMsg, aIter, &aResult->deltaMode) &&
       ReadParam(aMsg, aIter, &aResult->customizedByUserPrefs) &&
       ReadParam(aMsg, aIter, &aResult->isMomentum) &&
-      ReadParam(aMsg, aIter, &aResult->isPixelOnlyDevice) &&
+      ReadParam(aMsg, aIter, &aResult->mIsNoLineOrPageDelta) &&
       ReadParam(aMsg, aIter, &aResult->lineOrPageDeltaX) &&
       ReadParam(aMsg, aIter, &aResult->lineOrPageDeltaY) &&
       ReadParam(aMsg, aIter, &scrollType) &&
       ReadParam(aMsg, aIter, &aResult->overflowDeltaX) &&
       ReadParam(aMsg, aIter, &aResult->overflowDeltaY);
     aResult->scrollType =
       static_cast<mozilla::WidgetWheelEvent::ScrollType>(scrollType);
     return rv;
--- a/widget/windows/nsWinGesture.cpp
+++ b/widget/windows/nsWinGesture.cpp
@@ -571,17 +571,17 @@ nsWinGesture::PanDeltaToPixelScroll(Widg
 {
   aWheelEvent.deltaX = aWheelEvent.deltaY = aWheelEvent.deltaZ = 0.0;
   aWheelEvent.lineOrPageDeltaX = aWheelEvent.lineOrPageDeltaY = 0;
 
   aWheelEvent.refPoint.x = mPanRefPoint.x;
   aWheelEvent.refPoint.y = mPanRefPoint.y;
   aWheelEvent.deltaMode = nsIDOMWheelEvent::DOM_DELTA_PIXEL;
   aWheelEvent.scrollType = WidgetWheelEvent::SCROLL_SYNCHRONOUSLY;
-  aWheelEvent.isPixelOnlyDevice = true;
+  aWheelEvent.mIsNoLineOrPageDelta = true;
 
   aWheelEvent.overflowDeltaX = 0.0;
   aWheelEvent.overflowDeltaY = 0.0;
 
   // Don't scroll the view if we are currently at a bounds, or, if we are
   // panning back from a max feedback position. This keeps the original drag point
   // constant.
   if (!mXAxisFeedback) {