Add a "forwarded" flag to usergesture tokens.

Source/web/tests/WebUserGestureTokenTest.cpp

 /*
  * Copyright (C) 2013 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 61 matching lines @@
     }
 
     EXPECT_FALSE(token.hasGestures());
 
     {
         WebScopedUserGesture indicator(token);
         EXPECT_FALSE(WebUserGestureIndicator::isProcessingUserGesture());
     }
 
     EXPECT_TRUE(UserGestureIndicator::processedUserGestureInPast());
+
+    EXPECT_FALSE(token.wasForwarded());
+    token.setForwarded();
+    EXPECT_TRUE(token.wasForwarded());
 }
 
 }