Explicitly suppress scrolling for wheel events that will trigger zooming

content/renderer/input/input_handler_proxy.cc

Index: content/renderer/input/input_handler_proxy.cc
diff --git a/content/renderer/input/input_handler_proxy.cc b/content/renderer/input/input_handler_proxy.cc
index 21f3359f90736ba35e32a8f552cf8add554352d3..1009bd8e0afedd3bb6f9b8b3fec441d78ace73e5 100644
--- a/content/renderer/input/input_handler_proxy.cc
+++ b/content/renderer/input/input_handler_proxy.cc
@@ -293,9 +293,9 @@ InputHandlerProxy::EventDisposition InputHandlerProxy::HandleMouseWheel(
     // TODO(jamesr): We don't properly handle scroll by page in the compositor
     // thread, so punt it to the main thread. http://crbug.com/236639
     result = DID_NOT_HANDLE;
-  } else if (wheel_event.modifiers & WebInputEvent::ControlKey) {
-    // Wheel events involving the control key never trigger scrolling, only
-    // event handlers.  Forward to the main thread.
+  } else if (!wheel_event.canScroll) {
+    // Wheel events involving the control key with canScroll false will not

[tdresser, 2014/12/02 15:37:38]

I don't think you need to reference both the control key and |canScroll|. 

I'd say something like:
// Wheel events with |canScroll| == false will not trigger scrolling, ....

[lanwei, 2014/12/02 22:28:06]

Done.

+    // trigger scrolling, only event handlers.  Forward to the main thread.
     result = DID_NOT_HANDLE;
   } else if (smooth_scroll_enabled_) {
     cc::InputHandler::ScrollStatus scroll_status =