Add builders for tracing event's structural arguments

cc/trees/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_TREES_LAYER_TREE_HOST_H_
 #define CC_TREES_LAYER_TREE_HOST_H_
 
 #include <limits>
 #include <list>
 #include <set>
@@ skipping 239 matching lines @@
 
   HeadsUpDisplayLayer* hud_layer() const { return hud_layer_.get(); }
 
   Proxy* proxy() const { return proxy_.get(); }
 
   AnimationRegistrar* animation_registrar() const {
     return animation_registrar_.get();
   }
 
   // Obtains a thorough dump of the LayerTreeHost as a value.
-  scoped_ptr<base::Value> AsValue() const;
+  void AsValueInto(base::debug::TracedValue* value) const;
 
   bool in_paint_layer_contents() const { return in_paint_layer_contents_; }
 
   // CreateUIResource creates a resource given a bitmap.  The bitmap is
   // generated via an interface function, which is called when initializing the
   // resource and when the resource has been lost (due to lost context).  The
   // parameter of the interface is a single boolean, which indicates whether the
   // resource has been lost or not.  CreateUIResource returns an Id of the
   // resource, which is always positive.
   virtual UIResourceId CreateUIResource(UIResourceClient* client);
@@ skipping 183 matching lines @@
 
   ScopedPtrVector<SwapPromise> swap_promise_list_;
   std::set<SwapPromiseMonitor*> swap_promise_monitor_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerTreeHost);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_HOST_H_