Fixing flakiness of TextureLayerChangeInvisibleMailboxTest

cc/trees/proxy_main.h

Index: cc/trees/proxy_main.h
diff --git a/cc/trees/proxy_main.h b/cc/trees/proxy_main.h
index 3d97276193aa75690a6e8c6d0c2c5a60e9b1d57d..9fb7823df770e8db1cf80d98843df56bf71cbdc6 100644
--- a/cc/trees/proxy_main.h
+++ b/cc/trees/proxy_main.h
@@ -129,6 +129,10 @@ class CC_EXPORT ProxyMain : public Proxy {
   // run before we destroy it on the impl thread.
   std::unique_ptr<ProxyImpl> proxy_impl_;
 
+  // WeakPtrs generated by this factory will be invalidated when
+  // CompositorFrameSink is released.
+  base::WeakPtrFactory<ProxyMain> frame_sink_bound_weak_factory_;
+
   base::WeakPtrFactory<ProxyMain> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ProxyMain);