Add API to route end of fling messages from WebLayerTreeView to InputHandler

cc/thread_proxy.h

Index: cc/thread_proxy.h
diff --git a/cc/thread_proxy.h b/cc/thread_proxy.h
index da4f3868eddfb01ff385e71323e828bdcb731ae8..1b3c953698bdc7dcee47abb4e6e23469a0eac59c 100644
--- a/cc/thread_proxy.h
+++ b/cc/thread_proxy.h
@@ -48,6 +48,7 @@ public:
     virtual void setDeferCommits(bool) OVERRIDE;
     virtual bool commitRequested() const OVERRIDE;
     virtual void didAddAnimation() OVERRIDE { }
+    virtual void mainThreadHasStoppedFlinging() OVERRIDE;
     virtual void start() OVERRIDE;
     virtual void stop() OVERRIDE;
     virtual size_t maxPartialTextureUpdates() const OVERRIDE;