Add support for tagging layers.

cc/layer_tree_host.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_LAYER_TREE_HOST_H_
 #define CC_LAYER_TREE_HOST_H_
 
 #include <limits>
 
 #include "base/basictypes.h"
@@ skipping 183 matching lines @@
 
     void setDeviceScaleFactor(float);
     float deviceScaleFactor() const { return m_deviceScaleFactor; }
 
     HeadsUpDisplayLayer* hudLayer() const { return m_hudLayer.get(); }
 
     Proxy* proxy() const { return m_proxy.get(); }
 
     AnimationRegistrar* animationRegistrar() const { return m_animationRegistrar.get(); }
 
+    Layer* getFirstLayerWithTags(unsigned int tags) const;
+
 protected:
     LayerTreeHost(LayerTreeHostClient*, const LayerTreeSettings&);
     bool initialize(scoped_ptr<Thread> implThread);
     bool initializeForTesting(scoped_ptr<Proxy> proxyForTesting);
 
 private:
     typedef std::vector<scoped_refptr<Layer> > LayerList;
 
     bool initializeProxy(scoped_ptr<Proxy> proxy);
     void initializeRenderer();
@@ skipping 64 matching lines @@
     scoped_ptr<AnimationRegistrar> m_animationRegistrar;
 
     static bool s_needsFilterContext;
 
     DISALLOW_COPY_AND_ASSIGN(LayerTreeHost);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYER_TREE_HOST_H_