Backed out changeset 17792fad126f (bug 1368208) for reftestfailures in 508816-1.xul
authorCarsten "Tomcat" Book <cbook@mozilla.com>
Wed, 31 May 2017 12:31:40 +0200
changeset 409601 d840ee711bc8ad51a0e198b4f7991b8c842d07d4
parent 409600 d29a7708e35770728bd88d3218c495a2b1bb71e6
child 409602 928bbb8a26663119a9b4253efc6b760a53ccf936
push id7391
push usermtabara@mozilla.com
push dateMon, 12 Jun 2017 13:08:53 +0000
treeherdermozilla-beta@2191d7f87e2e [default view] [failures only]
perfherder[talos] [build metrics] [platform microbench] (compared to previous push)
bugs1368208, 508816
milestone55.0a1
backs out17792fad126f6b6737f4282f9f52af58b9246792
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
Backed out changeset 17792fad126f (bug 1368208) for reftestfailures in 508816-1.xul
toolkit/content/widgets/scrollbox.xml
--- a/toolkit/content/widgets/scrollbox.xml
+++ b/toolkit/content/widgets/scrollbox.xml
@@ -180,85 +180,57 @@
           var innerRect = {};
           innerRect.left = outerRect.left - this._scrollbox.scrollLeft;
           innerRect.top = outerRect.top - this._scrollbox.scrollTop;
           innerRect.right = innerRect.left + this._scrollbox.scrollWidth;
           innerRect.bottom = innerRect.top + this._scrollbox.scrollHeight;
           return innerRect;
         ]]></getter>
       </property>
-      <field name="scrollboxPaddingStart"><![CDATA[
-        parseFloat(window.getComputedStyle(this._scrollbox)[
-          this._isRTLScrollbox ? "paddingRight" : "paddingLeft"
-        ]);
-      ]]></field>
-      <field name="scrollboxPaddingEnd"><![CDATA[
-        parseFloat(window.getComputedStyle(this._scrollbox)[
-          this._isRTLScrollbox ? "paddingLeft" : "paddingRight"
-        ]);
-      ]]></field>
+      <property name="scrollboxPaddingStart" readonly="true">
+        <getter><![CDATA[
+          var ltr = (window.getComputedStyle(this).direction == "ltr");
+          var paddingStartName = ltr ? "padding-left" : "padding-right";
+          var scrollboxStyle = window.getComputedStyle(this._scrollbox);
+          return parseFloat(scrollboxStyle.getPropertyValue(paddingStartName));
+        ]]></getter>
+      </property>
       <property name="scrollPosition">
         <getter><![CDATA[
           return this.orient == "vertical" ?
                  this._scrollbox.scrollTop :
                  this._scrollbox.scrollLeft;
         ]]></getter>
         <setter><![CDATA[
           if (this.orient == "vertical")
             this._scrollbox.scrollTop = val;
           else
             this._scrollbox.scrollLeft = val;
           return val;
         ]]></setter>
       </property>
 
-      <field name="_startEndProps"><![CDATA[
-        this.orient == "vertical" ? ["top", "bottom"] : ["left", "right"];
-      ]]></field>
+      <property name="_startEndProps" readonly="true">
+        <getter><![CDATA[
+          return this.orient == "vertical" ?
+                 ["top", "bottom"] : ["left", "right"];
+        ]]></getter>
+      </property>
 
       <field name="_isRTLScrollbox"><![CDATA[
         this.orient != "vertical" &&
         document.defaultView.getComputedStyle(this._scrollbox).direction == "rtl";
       ]]></field>
 
       <field name="_scrollTarget">null</field>
 
-      <method name="_boundsWithoutFlushing">
-        <parameter name="element"/>
-        <body><![CDATA[
-          if (!("_DOMWindowUtils" in this)) {
-            try {
-              this._DOMWindowUtils =
-                window.QueryInterface(Components.interfaces.nsIInterfaceRequestor)
-                      .getInterface(Components.interfaces.nsIDOMWindowUtils);
-            } catch (e) {
-              // Can't access nsIDOMWindowUtils if we're unprivileged.
-              this._DOMWindowUtils = null;
-            }
-          }
-
-          return this._DOMWindowUtils ?
-                 this._DOMWindowUtils.getBoundsWithoutFlushing(element) :
-                 element.getBoundingClientRect();
-        ]]></body>
-      </method>
-
       <method name="_canScrollToElement">
         <parameter name="element"/>
         <body><![CDATA[
-          if (element.hidden) {
-            return false;
-          }
-
-          // See if the element is hidden via CSS without the hidden attribute.
-          // If we get only zeros for the client rect, this means the element
-          // is hidden. As a performance optimization, we don't flush layout
-          // here which means that on the fly changes aren't fully supported.
-          let rect = this._boundsWithoutFlushing(element);
-          return !!(rect.top || rect.left || rect.width || rect.height);
+          return window.getComputedStyle(element).display != "none";
         ]]></body>
       </method>
 
       <method name="ensureElementIsVisible">
         <parameter name="element"/>
         <parameter name="aSmoothScroll"/>
         <body><![CDATA[
           if (!this._canScrollToElement(element))
@@ -634,78 +606,50 @@
           if (this._isScrolling) {
             this._scrollAnim.stop();
             this._isScrolling = 0;
             this._scrollTarget = null;
           }
         ]]></body>
       </method>
 
-      <field name="_scrollButtonUpdatePending">false</field>
       <method name="_updateScrollButtonsDisabledState">
+        <parameter name="aScrolling"/>
         <body><![CDATA[
+          let scrolledToStart;
+          let scrolledToEnd;
+
+          // Avoid flushing layout when not overflowing or when scrolling.
           if (this.hasAttribute("notoverflowing")) {
-            this.setAttribute("scrolledtoend", "true");
-            this.setAttribute("scrolledtostart", "true");
-            return;
+            scrolledToStart = true;
+            scrolledToEnd = true;
+          } else if (aScrolling) {
+            scrolledToStart = false;
+            scrolledToEnd = false;
+          } else if (this.scrollPosition == 0) {
+            // In the RTL case, this means the _last_ element in the
+            // scrollbox is visible
+            scrolledToEnd = this._isRTLScrollbox;
+            scrolledToStart = !this._isRTLScrollbox;
+          } else if (this.scrollClientSize + this.scrollPosition == this.scrollSize) {
+            // In the RTL case, this means the _first_ element in the
+            // scrollbox is visible
+            scrolledToStart = this._isRTLScrollbox;
+            scrolledToEnd = !this._isRTLScrollbox;
           }
 
-          if (this._scrollButtonUpdatePending) {
-            return;
-          }
-          this._scrollButtonUpdatePending = true;
-
-          // Wait until after the next paint to get current layout data from
-          // getBoundsWithoutFlushing.
-          window.requestAnimationFrame(() => {
-            window.requestAnimationFrame(() => {
-              this._scrollButtonUpdatePending = false;
-
-              let scrolledToStart = false;
-              let scrolledToEnd = false;
-
-              if (this.hasAttribute("notoverflowing")) {
-                scrolledToStart = true;
-                scrolledToEnd = true;
-              } else {
-                let scrollboxPaddingStart = Math.round(this.scrollboxPaddingStart);
-                let scrollboxPaddingEnd = Math.round(this.scrollboxPaddingEnd);
-                let [start, end] = this._startEndProps;
-                if (this._isRTLScrollbox) {
-                  [start, end] = [end, start];
-                  scrollboxPaddingStart = -scrollboxPaddingStart;
-                  scrollboxPaddingEnd = -scrollboxPaddingEnd;
-                }
+          if (scrolledToEnd)
+            this.setAttribute("scrolledtoend", "true");
+          else
+            this.removeAttribute("scrolledtoend");
 
-                let scrollboxRect = this._boundsWithoutFlushing(this._scrollbox);
-                let elements = this._getScrollableElements();
-                let [firstElement, lastElement] = [elements[0], elements[elements.length - 1]];
-
-                if (firstElement &&
-                    this._boundsWithoutFlushing(firstElement)[start] - scrollboxPaddingStart == scrollboxRect[start]) {
-                  scrolledToStart = true;
-                } else if (lastElement &&
-                           this._boundsWithoutFlushing(lastElement)[end] + scrollboxPaddingEnd == scrollboxRect[end]) {
-                  scrolledToEnd = true;
-                }
-              }
-
-              if (scrolledToEnd) {
-                this.setAttribute("scrolledtoend", "true");
-              } else {
-                this.removeAttribute("scrolledtoend");
-              }
-
-              if (scrolledToStart) {
-                this.setAttribute("scrolledtostart", "true");
-              } else {
-                this.removeAttribute("scrolledtostart");
-              }
-            });
-          });
+          if (scrolledToStart)
+            this.setAttribute("scrolledtostart", "true");
+          else
+            this.removeAttribute("scrolledtostart");
         ]]></body>
       </method>
     </implementation>
 
     <handlers>
       <handler event="wheel"><![CDATA[
         let doScroll = false;
         let useSmoothScroll = event.deltaMode != event.DOM_DELTA_PIXEL && this.smoothScroll;
@@ -848,17 +792,37 @@
           // as the whole overflow event should not be happening in that case.
           this._updateScrollButtonsDisabledState();
         } catch (e) {
           this.setAttribute("notoverflowing", "true");
         }
       ]]></handler>
 
       <handler event="scroll"><![CDATA[
-        this._updateScrollButtonsDisabledState();
+        if (!this._delayedUpdateScrollButtonsTimer) {
+          // This is the beginning of a scrolling animation. We need to update
+          // scroll buttons now in case we were scrolled to the start or to the
+          // end before we started scrolling.
+          this._updateScrollButtonsDisabledState(true);
+        } else {
+          // We're in the middle of the scrolling animation. We'll restart the
+          // delayed update request so that we only update the scroll buttons
+          // a second time once we're done scrolling.
+          window.clearTimeout(this._delayedUpdateScrollButtonsTimer);
+        }
+
+        // Try to detect the end of the scrolling animation to update the
+        // scroll buttons again. To avoid false positives, this timeout needs
+        // to be big enough to account for intermediate frames that don't move
+        // the scroll position in case we're scrolling slowly.
+        this._delayedUpdateScrollButtonsTimer = setTimeout(() => {
+          // Scrolling animation has finished.
+          this._delayedUpdateScrollButtonsTimer = 0;
+          this._updateScrollButtonsDisabledState();
+        }, 200);
       ]]></handler>
     </handlers>
   </binding>
 
   <binding id="autorepeatbutton" extends="chrome://global/content/bindings/scrollbox.xml#scrollbox-base">
     <content repeat="hover">
       <xul:image class="autorepeatbutton-icon"/>
     </content>