Honor the wheel event canScroll bit instead of trying to infer it from the ctrl modifier

Source/platform/scroll/ScrollableArea.cpp

Index: Source/platform/scroll/ScrollableArea.cpp
diff --git a/Source/platform/scroll/ScrollableArea.cpp b/Source/platform/scroll/ScrollableArea.cpp
index f1704953f0a5b59e98c1fe0d1817a5658c6be6a6..9af7f883704a6b8857ffd0db902646255f1cbad8 100644
--- a/Source/platform/scroll/ScrollableArea.cpp
+++ b/Source/platform/scroll/ScrollableArea.cpp
@@ -239,8 +239,8 @@ bool ScrollableArea::scrollBehaviorFromString(const String& behaviorString, Scro
 
 bool ScrollableArea::handleWheelEvent(const PlatformWheelEvent& wheelEvent)
 {
-    // ctrl+wheel events are used to trigger zooming, not scrolling.
-    if (wheelEvent.modifiers() & PlatformEvent::CtrlKey)
+    // Method suppressScroll() are used to trigger zooming, not scrolling.

[tdresser, 2014/11/27 15:06:09]

Reword to:

Wheel events whose scrolling has been suppressed are used to trigger zooming,
not scrolling.

[lanwei, 2014/12/02 15:48:10]

Done.

+    if (wheelEvent.suppressScroll())
         return false;
 
     cancelProgrammaticScrollAnimation();