Initial attempt at counting layers in the compositor thread.

cc/trees/layer_tree_impl.h

 // Copyright 2012 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_LAYER_TREE_IMPL_H_
 #define CC_TREES_LAYER_TREE_IMPL_H_
 
 #include <list>
 #include <string>
 #include <vector>
@@ skipping 258 matching lines @@
                          const LayerSelectionBound& focus);
 
   // Compute the current selection handle location and visbility with respect to
   // the viewport.
   void GetViewportSelection(ViewportSelectionBound* anchor,
                             ViewportSelectionBound* focus);
 
   void RegisterPictureLayerImpl(PictureLayerImpl* layer);
   void UnregisterPictureLayerImpl(PictureLayerImpl* layer);
 
+  size_t NumLayers();
+
  protected:
   explicit LayerTreeImpl(LayerTreeHostImpl* layer_tree_host_impl);
   void ReleaseResourcesRecursive(LayerImpl* current);
 
   LayerTreeHostImpl* layer_tree_host_impl_;
   int source_frame_number_;
   scoped_ptr<LayerImpl> root_layer_;
   HeadsUpDisplayLayerImpl* hud_layer_;
   LayerImpl* currently_scrolling_layer_;
   LayerScrollOffsetDelegate* root_layer_scroll_offset_delegate_;
@@ skipping 45 matching lines @@
 
   int render_surface_layer_list_id_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(LayerTreeImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_IMPL_H_