Merge 112363 - [chromium] Send wheel events to main thread even if we think nothing is scrollable

Source/WebKit/chromium/src/WebCompositorInputHandlerImpl.cpp

Index: Source/WebKit/chromium/src/WebCompositorInputHandlerImpl.cpp
===================================================================
--- Source/WebKit/chromium/src/WebCompositorInputHandlerImpl.cpp	(revision 112599)
+++ Source/WebKit/chromium/src/WebCompositorInputHandlerImpl.cpp	(working copy)
@@ -187,7 +187,9 @@
             return DidHandle;
         }
         case CCInputHandlerClient::ScrollIgnored:
-            return DropEvent;
+            // FIXME: This should be DropEvent, but in cases where we fail to properly sync scrollability it's safer to send the
+            // event to the main thread. Change back to DropEvent once we have synchronization bugs sorted out.
+            return DidNotHandle; 
         case CCInputHandlerClient::ScrollFailed:
             return DidNotHandle;
         }