Add builders for tracing event's structural arguments

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 10 matching lines @@
 namespace BASE_HASH_NAMESPACE {
 template<>
 struct hash<cc::LayerImpl*> {
   size_t operator()(cc::LayerImpl* ptr) const {
     return hash<size_t>()(reinterpret_cast<size_t>(ptr));
   }
 };
 }  // namespace BASE_HASH_NAMESPACE
 #endif  // COMPILER
 
+namespace base {
+namespace debug {
+class TracedValue;
+}
+}
+
 namespace cc {
 
 class ContextProvider;
 class DebugRectHistory;
 class FrameRateCounter;
 class HeadsUpDisplayLayerImpl;
 class LayerScrollOffsetDelegateProxy;
 class LayerTreeDebugState;
 class LayerTreeHostImpl;
 class LayerTreeImpl;
@@ skipping 58 matching lines @@
 
   // Tree specific methods exposed to layer-impl tree.
   // ---------------------------------------------------------------------------
   void SetNeedsRedraw();
 
   // TODO(nduca): These are implemented in cc files temporarily, but will become
   // trivial accessors in a followup patch.
   const LayerTreeDebugState& debug_state() const;
   float device_scale_factor() const;
   DebugRectHistory* debug_rect_history() const;
-  scoped_ptr<base::Value> AsValue() const;
+  void AsValueInto(base::debug::TracedValue* dict) const;
 
   // Other public methods
   // ---------------------------------------------------------------------------
   LayerImpl* root_layer() const { return root_layer_.get(); }
   void SetRootLayer(scoped_ptr<LayerImpl>);
   scoped_ptr<LayerImpl> DetachLayerTree();
 
   void PushPropertiesTo(LayerTreeImpl* tree_impl);
 
   int source_frame_number() const { return source_frame_number_; }
@@ skipping 226 matching lines @@
 
   int render_surface_layer_list_id_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(LayerTreeImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_IMPL_H_