Add LayerTreeHostSettings for synchronous compositor

cc/trees/thread_proxy.h

 // Copyright 2011 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_THREAD_PROXY_H_
 #define CC_TREES_THREAD_PROXY_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/time.h"
@@ skipping 230 matching lines @@
       current_resource_update_controller_on_impl_thread_;
 
   // Set when the next draw should post DidCommitAndDrawFrame to the main
   // thread.
   bool next_frame_is_newly_committed_frame_on_impl_thread_;
 
   bool render_vsync_enabled_;
   bool render_vsync_notification_enabled_;
   VSyncClient* vsync_client_;
 
+  bool enable_synchronous_compositing_;
+
   bool inside_draw_;
 
   bool defer_commits_;
   scoped_ptr<BeginFrameAndCommitState> pending_deferred_commit_;
 
   base::TimeTicks smoothness_takes_priority_expiration_time_;
   bool renew_tree_priority_on_impl_thread_pending_;
 
   DISALLOW_COPY_AND_ASSIGN(ThreadProxy);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_THREAD_PROXY_H_