Don't count modifiers-changed events as being user gestures.

third_party/WebKit/public/platform/Platform.h

 /*
  * Copyright (C) 2012 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 608 matching lines @@
   // are based on the value defined in ui/events/keycodes/dom3/dom_key_data.h.
   // Returns empty string, if DOM key value is not found.
   virtual WebString DomKeyStringFromEnum(int dom_key) { return WebString(); }
 
   // This method converts from the suppled DOM |key| value to the
   // embedder's DOM |key| enum for the key pressed. |keyString| is defined in
   // ui/events/keycodes/dom3/dom_key_data.h.
   // Returns 0 if DOM key enum is not found.
   virtual int DomKeyEnumFromString(const WebString& key_string) { return 0; }
 
+  // This method returns whether the specified |domKey| is a modifier key.
+  // |domKey| values are based on the value defined in
+  // ui/events/keycodes/dom3/dom_key_data.h.
+  virtual bool IsDomKeyForModifier(int dom_key) { return false; }
+
   // Quota -----------------------------------------------------------
 
   // Queries the storage partition's storage usage and quota information.
   // WebStorageQuotaCallbacks::didQueryStorageUsageAndQuota will be called
   // with the current usage and quota information for the partition. When
   // an error occurs WebStorageQuotaCallbacks::didFail is called with an
   // error code.
   virtual void QueryStorageUsageAndQuota(const WebURL& storage_partition,
                                          WebStorageQuotaType,
                                          WebStorageQuotaCallbacks) {}
@@ skipping 51 matching lines @@
  protected:
   Platform();
   virtual ~Platform() {}
 
   WebThread* main_thread_;
 };
 
 }  // namespace blink
 
 #endif