Add a "forwarded" flag to usergesture tokens.

Source/web/tests/WebUserGestureTokenTest.cpp

Index: Source/web/tests/WebUserGestureTokenTest.cpp
diff --git a/Source/web/tests/WebUserGestureTokenTest.cpp b/Source/web/tests/WebUserGestureTokenTest.cpp
index 7055fb63224cd50c1e7b8a01026b3de97a3a152e..1ca236f99cacc26a8ad326aee3ba472889c00697 100644
--- a/Source/web/tests/WebUserGestureTokenTest.cpp
+++ b/Source/web/tests/WebUserGestureTokenTest.cpp
@@ -79,6 +79,10 @@ TEST(WebUserGestureTokenTest, Basic)
     }
 
     EXPECT_TRUE(UserGestureIndicator::processedUserGestureInPast());
+
+    EXPECT_FALSE(token.wasForwarded());
+    token.setForwarded();
+    EXPECT_TRUE(token.wasForwarded());
 }
 
 }