[Mac] Don't dispatch wheel events for PhaseMayBegin|Cancelled|Ended

third_party/WebKit/Source/core/input/EventHandler.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2012 Digia Plc. and/or its subsidiary(-ies)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 1575 matching lines @@
             // Use WebFocusTypeForward instead of WebFocusTypeMouse here to mean the focus has slided.
             found->focus(FocusParams(SelectionBehaviorOnFocus::Reset, WebFocusTypeForward, nullptr));
             return true;
         }
     }
     return false;
 }
 
 WebInputEventResult EventHandler::handleWheelEvent(const PlatformWheelEvent& event)
 {
+#if OS(MACOSX)
+    // Filter Mac OS specific phases, usually with a zero-delta.
+    // https://crbug.com/553732
+    // TODO(chongz): EventSender sends events with |PlatformWheelEventPhaseNone|, but it shouldn't.
+    const int kPlatformWheelEventPhaseNoEventMask = PlatformWheelEventPhaseEnded | PlatformWheelEventPhaseCancelled | PlatformWheelEventPhaseMayBegin;
+    if ((event.phase() & kPlatformWheelEventPhaseNoEventMask) || (event.momentumPhase() & kPlatformWheelEventPhaseNoEventMask))
+        return WebInputEventResult::NotHandled;
+#endif
     Document* doc = m_frame->document();
 
     if (doc->layoutViewItem().isNull())
         return WebInputEventResult::NotHandled;
 
     FrameView* view = m_frame->view();
     if (!view)
         return WebInputEventResult::NotHandled;
 
     LayoutPoint vPoint = view->rootFrameToContents(event.position());
@@ skipping 1233 matching lines @@
 
 FrameHost* EventHandler::frameHost() const
 {
     if (!m_frame->page())
         return nullptr;
 
     return &m_frame->page()->frameHost();
 }
 
 } // namespace blink