Plumb phase/momentum for WheelEvent.

third_party/WebKit/Source/platform/PlatformWheelEvent.h

 /*
  * Copyright (C) 2004, 2005, 2006, 2009 Apple Inc. All rights reserved.
  *
  * 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.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 24 matching lines @@
 // The ScrollByPixelWheelEvent is a fine-grained event that specifies the precise number of pixels to scroll. It is sent directly by MacBook touchpads on OS X,
 // and synthesized in other cases where platforms generate line-by-line scrolling events.
 // The ScrollByPageWheelEvent indicates that the wheel event should scroll an entire page. In this case WebCore's built in paging behavior is used to page
 // up and down (you get the same behavior as if the user was clicking in a scrollbar track to page up or page down).
 enum PlatformWheelEventGranularity {
     ScrollByPageWheelEvent,
     ScrollByPixelWheelEvent,
 };
 
 #if OS(MACOSX)
+// Note: do to the use of static_casts to convert this type to WheelEventPhase,
+// and WheelEventPhase to WebMouseWheelEvent::Phase, the definition that follows
+// must be kept in sync with that used for the corresponding types.
 enum PlatformWheelEventPhase {
     PlatformWheelEventPhaseNone        = 0,
     PlatformWheelEventPhaseBegan       = 1 << 0,
     PlatformWheelEventPhaseStationary  = 1 << 1,
     PlatformWheelEventPhaseChanged     = 1 << 2,
     PlatformWheelEventPhaseEnded       = 1 << 3,
     PlatformWheelEventPhaseCancelled   = 1 << 4,
     PlatformWheelEventPhaseMayBegin    = 1 << 5,
 };
 #endif
@@ skipping 60 matching lines @@
     PlatformWheelEventPhase m_phase;
     PlatformWheelEventPhase m_momentumPhase;
     bool m_canRubberbandLeft;
     bool m_canRubberbandRight;
 #endif
 };
 
 } // namespace blink
 
 #endif // PlatformWheelEvent_h