--- a/content/events/src/Touch.h
+++ b/content/events/src/Touch.h
@@ -3,16 +3,17 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #ifndef mozilla_dom_Touch_h
 #define mozilla_dom_Touch_h
 
 #include "mozilla/Attributes.h"
 #include "nsWrapperCache.h"
+#include "nsAutoPtr.h"
 #include "Units.h"
 
 class nsPresContext;
 class nsEvent;
 
 namespace mozilla {
 namespace dom {
 

new file mode 100644
--- /dev/null
+++ b/gfx/src/AppUnits.h
@@ -0,0 +1,11 @@
+/* -*- Mode: C++; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef _NS_APPUNITS_H_
+#define _NS_APPUNITS_H_
+namespace mozilla {
+static int32_t AppUnitsPerCSSPixel() { return 60; }
+}
+#endif /* _NS_APPUNITS_H_ */

--- a/gfx/src/moz.build
+++ b/gfx/src/moz.build
@@ -29,16 +29,20 @@ EXPORTS += [
     'nsRect.h',
     'nsRegion.h',
     'nsRenderingContext.h',
     'nsSize.h',
     'nsThemeConstants.h',
     'nsTransform2D.h',
 ]
 
+EXPORTS.mozilla += [
+    'AppUnits.h',
+]
+
 if CONFIG['MOZ_X11']:
     EXPORTS.mozilla += ['X11Util.h']
     CPP_SOURCES += [
         'X11Util.cpp',
     ]
 
 CPP_SOURCES += [
     'gfxCrashReporterUtils.cpp',

--- a/gfx/src/nsDeviceContext.h
+++ b/gfx/src/nsDeviceContext.h
@@ -12,16 +12,17 @@
 #include "mozilla/Assertions.h"         // for MOZ_ASSERT_HELPER2
 #include "nsAutoPtr.h"                  // for nsRefPtr
 #include "nsCOMPtr.h"                   // for nsCOMPtr
 #include "nsCoord.h"                    // for nscoord
 #include "nsError.h"                    // for nsresult
 #include "nsISupports.h"                // for NS_INLINE_DECL_REFCOUNTING
 #include "nsMathUtils.h"                // for NS_round
 #include "nscore.h"                     // for PRUnichar, nsAString
+#include "mozilla/AppUnits.h"           // for AppUnits
 
 class gfxASurface;
 class gfxUserFontSet;
 class nsFont;
 class nsFontCache;
 class nsFontMetrics;
 class nsIAtom;
 class nsIDeviceContextSpec;
@@ -60,17 +61,17 @@ public:
      * @return error status
      */
     nsresult CreateRenderingContext(nsRenderingContext *&aContext);
 
     /**
      * Gets the number of app units in one CSS pixel; this number is global,
      * not unique to each device context.
      */
-    static int32_t AppUnitsPerCSSPixel() { return 60; }
+    static int32_t AppUnitsPerCSSPixel() { return mozilla::AppUnitsPerCSSPixel(); }
 
     /**
      * Gets the number of app units in one device pixel; this number
      * is usually a factor of AppUnitsPerCSSPixel(), although that is
      * not guaranteed.
      */
     int32_t AppUnitsPerDevPixel() const { return mAppUnitsPerDevPixel; }
 

--- a/layout/base/Units.h
+++ b/layout/base/Units.h
@@ -7,16 +7,17 @@
 #ifndef MOZ_UNITS_H_
 #define MOZ_UNITS_H_
 
 #include "mozilla/gfx/Point.h"
 #include "mozilla/gfx/Rect.h"
 #include "mozilla/gfx/ScaleFactor.h"
 #include "nsDeviceContext.h"
 #include "nsRect.h"
+#include "mozilla/AppUnits.h"
 
 namespace mozilla {
 
 struct CSSPixel;
 struct LayoutDevicePixel;
 struct LayerPixel;
 struct ScreenPixel;
 
@@ -73,69 +74,69 @@ typedef gfx::ScaleFactor<ScreenPixel, Sc
 /*
  * The pixels that content authors use to specify sizes in.
  */
 struct CSSPixel {
 
   // Conversions from app units
 
   static CSSPoint FromAppUnits(const nsPoint& aPoint) {
-    return CSSPoint(NSAppUnitsToFloatPixels(aPoint.x, float(nsDeviceContext::AppUnitsPerCSSPixel())),
-                    NSAppUnitsToFloatPixels(aPoint.y, float(nsDeviceContext::AppUnitsPerCSSPixel())));
+    return CSSPoint(NSAppUnitsToFloatPixels(aPoint.x, float(AppUnitsPerCSSPixel())),
+                    NSAppUnitsToFloatPixels(aPoint.y, float(AppUnitsPerCSSPixel())));
   }
 
   static CSSRect FromAppUnits(const nsRect& aRect) {
-    return CSSRect(NSAppUnitsToFloatPixels(aRect.x, float(nsDeviceContext::AppUnitsPerCSSPixel())),
-                   NSAppUnitsToFloatPixels(aRect.y, float(nsDeviceContext::AppUnitsPerCSSPixel())),
-                   NSAppUnitsToFloatPixels(aRect.width, float(nsDeviceContext::AppUnitsPerCSSPixel())),
-                   NSAppUnitsToFloatPixels(aRect.height, float(nsDeviceContext::AppUnitsPerCSSPixel())));
+    return CSSRect(NSAppUnitsToFloatPixels(aRect.x, float(AppUnitsPerCSSPixel())),
+                   NSAppUnitsToFloatPixels(aRect.y, float(AppUnitsPerCSSPixel())),
+                   NSAppUnitsToFloatPixels(aRect.width, float(AppUnitsPerCSSPixel())),
+                   NSAppUnitsToFloatPixels(aRect.height, float(AppUnitsPerCSSPixel())));
   }
 
   static CSSIntPoint FromAppUnitsRounded(const nsPoint& aPoint) {
-    return CSSIntPoint(NSAppUnitsToIntPixels(aPoint.x, float(nsDeviceContext::AppUnitsPerCSSPixel())),
-                       NSAppUnitsToIntPixels(aPoint.y, float(nsDeviceContext::AppUnitsPerCSSPixel())));
+    return CSSIntPoint(NSAppUnitsToIntPixels(aPoint.x, float(AppUnitsPerCSSPixel())),
+                       NSAppUnitsToIntPixels(aPoint.y, float(AppUnitsPerCSSPixel())));
   }
 
   static CSSIntSize FromAppUnitsRounded(const nsSize& aSize)
   {
-    return CSSIntSize(NSAppUnitsToIntPixels(aSize.width, float(nsDeviceContext::AppUnitsPerCSSPixel())),
-                      NSAppUnitsToIntPixels(aSize.height, float(nsDeviceContext::AppUnitsPerCSSPixel())));
+    return CSSIntSize(NSAppUnitsToIntPixels(aSize.width, float(AppUnitsPerCSSPixel())),
+                      NSAppUnitsToIntPixels(aSize.height, float(AppUnitsPerCSSPixel())));
   }
 
   static CSSIntRect FromAppUnitsRounded(const nsRect& aRect) {
-    return CSSIntRect(NSAppUnitsToIntPixels(aRect.x, float(nsDeviceContext::AppUnitsPerCSSPixel())),
-                      NSAppUnitsToIntPixels(aRect.y, float(nsDeviceContext::AppUnitsPerCSSPixel())),
-                      NSAppUnitsToIntPixels(aRect.width, float(nsDeviceContext::AppUnitsPerCSSPixel())),
-                      NSAppUnitsToIntPixels(aRect.height, float(nsDeviceContext::AppUnitsPerCSSPixel())));
+    return CSSIntRect(NSAppUnitsToIntPixels(aRect.x, float(AppUnitsPerCSSPixel())),
+                      NSAppUnitsToIntPixels(aRect.y, float(AppUnitsPerCSSPixel())),
+                      NSAppUnitsToIntPixels(aRect.width, float(AppUnitsPerCSSPixel())),
+                      NSAppUnitsToIntPixels(aRect.height, float(AppUnitsPerCSSPixel())));
   }
 
   // Conversions to app units
 
   static nsPoint ToAppUnits(const CSSPoint& aPoint) {
-    return nsPoint(NSToCoordRoundWithClamp(aPoint.x * float(nsDeviceContext::AppUnitsPerCSSPixel())),
-                   NSToCoordRoundWithClamp(aPoint.y * float(nsDeviceContext::AppUnitsPerCSSPixel())));
+    return nsPoint(NSToCoordRoundWithClamp(aPoint.x * float(AppUnitsPerCSSPixel())),
+                   NSToCoordRoundWithClamp(aPoint.y * float(AppUnitsPerCSSPixel())));
   }
 
   static nsPoint ToAppUnits(const CSSIntPoint& aPoint) {
-    return nsPoint(NSToCoordRoundWithClamp(float(aPoint.x) * float(nsDeviceContext::AppUnitsPerCSSPixel())),
-                   NSToCoordRoundWithClamp(float(aPoint.y) * float(nsDeviceContext::AppUnitsPerCSSPixel())));
+    return nsPoint(NSToCoordRoundWithClamp(float(aPoint.x) * float(AppUnitsPerCSSPixel())),
+                   NSToCoordRoundWithClamp(float(aPoint.y) * float(AppUnitsPerCSSPixel())));
   }
 
   static nsRect ToAppUnits(const CSSRect& aRect) {
-    return nsRect(NSToCoordRoundWithClamp(aRect.x * float(nsDeviceContext::AppUnitsPerCSSPixel())),
-                  NSToCoordRoundWithClamp(aRect.y * float(nsDeviceContext::AppUnitsPerCSSPixel())),
-                  NSToCoordRoundWithClamp(aRect.width * float(nsDeviceContext::AppUnitsPerCSSPixel())),
-                  NSToCoordRoundWithClamp(aRect.height * float(nsDeviceContext::AppUnitsPerCSSPixel())));
+    return nsRect(NSToCoordRoundWithClamp(aRect.x * float(AppUnitsPerCSSPixel())),
+                  NSToCoordRoundWithClamp(aRect.y * float(AppUnitsPerCSSPixel())),
+                  NSToCoordRoundWithClamp(aRect.width * float(AppUnitsPerCSSPixel())),
+                  NSToCoordRoundWithClamp(aRect.height * float(AppUnitsPerCSSPixel())));
   }
 };
 
 /*
  * The pixels that are referred to as "device pixels" in layout code. In
  * general this is obtained by converting a value in app units value by the
- * nsDeviceContext::AppUnitsPerDevPixel() value. The size of these pixels
+ * AppUnitsPerDevPixel() value. The size of these pixels
  * are affected by:
  * 1) the "full zoom" (see nsPresContext::SetFullZoom)
  * 2) the "widget scale" (see nsIWidget::GetDefaultScale)
  */
 struct LayoutDevicePixel {
   static LayoutDeviceIntPoint FromUntyped(const nsIntPoint& aPoint) {
     return LayoutDeviceIntPoint(aPoint.x, aPoint.y);
   }

--- a/layout/base/nsPresContext.h
+++ b/layout/base/nsPresContext.h
@@ -27,16 +27,17 @@
 #include "nsChangeHint.h"
 #include <algorithm>
 // This also pulls in gfxTypes.h, which we cannot include directly.
 #include "gfxRect.h"
 #include "nsTArray.h"
 #include "nsAutoPtr.h"
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/TimeStamp.h"
+#include "mozilla/AppUnits.h"
 #include "prclist.h"
 #include "nsThreadUtils.h"
 #include "ScrollbarStyles.h"
 
 #ifdef IBMBIDI
 class nsBidiPresUtils;
 #endif // IBMBIDI
 
@@ -551,43 +552,43 @@ public:
    *
    * If |aChanged| is non-null, then aChanged is filled in with whether
    * the return value has changed since either:
    *  a. the last time the function was called with non-null aChanged, or
    *  b. the first time the function was called.
    */
   float ScreenWidthInchesForFontInflation(bool* aChanged = nullptr);
 
-  static int32_t AppUnitsPerCSSPixel() { return nsDeviceContext::AppUnitsPerCSSPixel(); }
+  static int32_t AppUnitsPerCSSPixel() { return mozilla::AppUnitsPerCSSPixel(); }
   int32_t AppUnitsPerDevPixel() const  { return mDeviceContext->AppUnitsPerDevPixel(); }
   static int32_t AppUnitsPerCSSInch() { return nsDeviceContext::AppUnitsPerCSSInch(); }
 
   static nscoord CSSPixelsToAppUnits(int32_t aPixels)
   { return NSToCoordRoundWithClamp(float(aPixels) *
-             float(nsDeviceContext::AppUnitsPerCSSPixel())); }
+             float(AppUnitsPerCSSPixel())); }
 
   static nscoord CSSPixelsToAppUnits(float aPixels)
   { return NSToCoordRoundWithClamp(aPixels *
-             float(nsDeviceContext::AppUnitsPerCSSPixel())); }
+             float(AppUnitsPerCSSPixel())); }
 
   static int32_t AppUnitsToIntCSSPixels(nscoord aAppUnits)
   { return NSAppUnitsToIntPixels(aAppUnits,
-             float(nsDeviceContext::AppUnitsPerCSSPixel())); }
+             float(AppUnitsPerCSSPixel())); }
 
   static float AppUnitsToFloatCSSPixels(nscoord aAppUnits)
   { return NSAppUnitsToFloatPixels(aAppUnits,
-             float(nsDeviceContext::AppUnitsPerCSSPixel())); }
+             float(AppUnitsPerCSSPixel())); }
 
   nscoord DevPixelsToAppUnits(int32_t aPixels) const
   { return NSIntPixelsToAppUnits(aPixels,
                                  mDeviceContext->AppUnitsPerDevPixel()); }
 
   int32_t AppUnitsToDevPixels(nscoord aAppUnits) const
   { return NSAppUnitsToIntPixels(aAppUnits,
-             float(mDeviceContext->AppUnitsPerDevPixel())); }
+             float(AppUnitsPerDevPixel())); }
 
   int32_t CSSPixelsToDevPixels(int32_t aPixels)
   { return AppUnitsToDevPixels(CSSPixelsToAppUnits(aPixels)); }
 
   float CSSPixelsToDevPixels(float aPixels)
   {
     return NSAppUnitsToFloatPixels(CSSPixelsToAppUnits(aPixels),
                                    float(mDeviceContext->AppUnitsPerDevPixel()));