Handle alternate types in HandleMouseEvent.

ui/base/events/event.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_BASE_EVENTS_EVENT_H_
 #define UI_BASE_EVENTS_EVENT_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/event_types.h"
@@ skipping 156 matching lines @@
     return type_ == ET_GESTURE_SCROLL_BEGIN ||
            type_ == ET_GESTURE_SCROLL_UPDATE ||
            type_ == ET_GESTURE_SCROLL_END;
   }
 
   bool IsFlingScrollEvent() const {
     return type_ == ET_SCROLL_FLING_CANCEL ||
            type_ == ET_SCROLL_FLING_START;
   }
 
+  bool IsMouseWheelEvent() const {
+    return type_ == ET_MOUSEWHEEL;

[sadrul, 2013/06/24 02:09:35]

This is simple enough that I wouldn't add it.

+  }
+
   // Returns true if the event has a valid |native_event_|.
   bool HasNativeEvent() const;
 
   // Immediately stops the propagation of the event. This must be called only
   // from an EventHandler during an event-dispatch. Any event handler that may
   // be in the list will not receive the event after this is called.
   // Note that StopPropagation() can be called only for cancelable events.
   void StopPropagation();
   bool stopped_propagation() const { return !!(result_ & ER_CONSUMED); }
 
@@ skipping 516 matching lines @@
   // This value is stored as a bitfield because the number of touch ids varies,
   // but we currently don't need more than 32 touches at a time.
   const unsigned int touch_ids_bitfield_;
 
   DISALLOW_COPY_AND_ASSIGN(GestureEvent);
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_EVENTS_EVENT_H_