Fixing flakiness of TextureLayerChangeInvisibleMailboxTest

cc/trees/proxy_main.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_TREES_PROXY_MAIN_H_
 #define CC_TREES_PROXY_MAIN_H_
 
 #include "base/macros.h"
 #include "cc/cc_export.h"
 #include "cc/input/browser_controls_state.h"
@@ skipping 111 matching lines @@
 
   bool defer_commits_;
 
   // ProxyImpl is created and destroyed on the impl thread, and should only be
   // accessed on the impl thread.
   // It is safe to use base::Unretained to post tasks to ProxyImpl on the impl
   // thread, since we control its lifetime. Any tasks posted to it are bound to
   // 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);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_PROXY_MAIN_H_