Articulate the cancel behavior in WebMouseWheelEvent.

third_party/WebKit/Source/web/WebInputEvent.cpp

 /*
  * Copyright (C) 2009 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 32 matching lines @@
 
 struct SameSizeAsWebKeyboardEvent : public SameSizeAsWebInputEvent {
     int keyboardData[14];
 };
 
 struct SameSizeAsWebMouseEvent : public SameSizeAsWebInputEvent {
     int mouseData[15];
 };
 
 struct SameSizeAsWebMouseWheelEvent : public SameSizeAsWebMouseEvent {
-    int mousewheelData[12];
+    int mousewheelData[13];
 };
 
 struct SameSizeAsWebGestureEvent : public SameSizeAsWebInputEvent {
     int gestureData[12];
 };
 
 struct SameSizeAsWebTouchEvent : public SameSizeAsWebInputEvent {
     WebTouchPoint touchPoints[WebTouchEvent::touchesLengthCap];
     int touchData[4];
 };
@@ skipping 127 matching lines @@
 {
     const char* id = staticKeyIdentifiers(windowsKeyCode);
     if (id) {
         strncpy(keyIdentifier, id, sizeof(keyIdentifier) - 1);
         keyIdentifier[sizeof(keyIdentifier) - 1] = '\0';
     } else
         snprintf(keyIdentifier, sizeof(keyIdentifier), "U+%04X", toupper(windowsKeyCode));
 }
 
 } // namespace blink