From 0b58db3fc6a0ca067499bdd9f634afa6d1bf2e84 Mon Sep 17 00:00:00 2001
From: Wes Kocher <wkocher@mozilla.com>
Date: Thu, 14 Apr 2016 11:05:01 -0700
Subject: [PATCH] Backed out changeset 954189d579d5 (bug 1263975) for failures
 in test_mousescroll.xul

MozReview-Commit-ID: 9fXzw19FUeb
---
 toolkit/content/widgets/scrollbox.xml | 29 +++++++++++++--------------
 1 file changed, 14 insertions(+), 15 deletions(-)

diff --git a/toolkit/content/widgets/scrollbox.xml b/toolkit/content/widgets/scrollbox.xml
index ede284ae7de0..51dffdc2c031 100644
--- a/toolkit/content/widgets/scrollbox.xml
+++ b/toolkit/content/widgets/scrollbox.xml
@@ -497,12 +497,12 @@
     </implementation>
 
     <handlers>
-      <handler event="wheel"><![CDATA[
+      <handler event="DOMMouseScroll"><![CDATA[
         if (this.orient == "vertical") {
-          if (event.deltaMode == event.DOM_DELTA_PIXEL)
-            this.scrollByPixels(event.deltaY);
-          else
-            this.scrollByIndex(event.deltaY);
+          // prevent horizontal scrolling from scrolling a vertical scrollbox
+          if (event.axis == event.HORIZONTAL_AXIS)
+            return;
+          this.scrollByIndex(event.detail);
         }
         // We allow vertical scrolling to scroll a horizontal scrollbox
         // because many users have a vertical scroll wheel but no
@@ -511,18 +511,12 @@
         // and mouse wheels that support simultaneous scrolling in both axes.
         // We do this by scrolling only when the last two scroll events were
         // on the same axis as the current scroll event.
-        // For diagonal scroll events we only respect the dominant axis.
         else {
-          let isVertical = Math.abs(event.deltaY) > Math.abs(event.deltaX);
-          let delta = isVertical ? event.deltaY : event.deltaX;
-          let scrollByDelta = isVertical && this._isRTLScrollbox ? -delta : delta;
+          let isVertical = event.axis == event.VERTICAL_AXIS;
 
-          if (this._prevMouseScrolls.every(prev => prev == isVertical)) {
-            if (event.deltaMode == event.DOM_DELTA_PIXEL)
-              this.scrollByPixels(scrollByDelta);
-            else
-              this.scrollByIndex(scrollByDelta);
-          }
+          if (this._prevMouseScrolls.every(prev => prev == isVertical))
+            this.scrollByIndex(isVertical && this._isRTLScrollbox ? -event.detail :
+                                                                    event.detail);
 
           if (this._prevMouseScrolls.length > 1)
             this._prevMouseScrolls.shift();
@@ -533,6 +527,11 @@
         event.preventDefault();
       ]]></handler>
 
+      <handler event="MozMousePixelScroll"><![CDATA[
+        event.stopPropagation();
+        event.preventDefault();
+      ]]></handler>
+
       <handler event="underflow" phase="capturing"><![CDATA[
         // filter underflow events which were dispatched on nested scrollboxes
         if (event.target != this)