Compositor thread plumbing for layout rectangle debug info.

cc/layers/layer_client.h

 // Copyright 2013 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_LAYERS_LAYER_CLIENT_H_
 #define CC_LAYERS_LAYER_CLIENT_H_
 
 #include <string>
 
 #include "cc/base/cc_export.h"
 
+namespace base {
+namespace debug {
+class ConvertableToTraceFormat;
+}
+}
+
 namespace cc {
 
 class CC_EXPORT LayerClient {
  public:
   virtual std::string DebugName() = 0;
 
  protected:
   virtual ~LayerClient() {}
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_LAYER_CLIENT_H_