Add builders for tracing event's structural arguments

cc/resources/image_raster_worker_pool.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_RESOURCES_IMAGE_RASTER_WORKER_POOL_H_
 #define CC_RESOURCES_IMAGE_RASTER_WORKER_POOL_H_
 
 #include "base/memory/weak_ptr.h"
 #include "base/values.h"
 #include "cc/resources/raster_worker_pool.h"
 #include "cc/resources/rasterizer.h"
 
+namespace base {
+namespace debug {
+class ConvertableToTraceFormat;
+}
+}
+
 namespace cc {
 class ResourceProvider;
 
 class CC_EXPORT ImageRasterWorkerPool : public RasterWorkerPool,
                                         public Rasterizer,
                                         public RasterizerTaskClient {
  public:
   virtual ~ImageRasterWorkerPool();
 
   static scoped_ptr<RasterWorkerPool> Create(
@@ skipping 15 matching lines @@
   virtual void ReleaseCanvasForRaster(RasterTask* task) OVERRIDE;
 
  protected:
   ImageRasterWorkerPool(base::SequencedTaskRunner* task_runner,
                         TaskGraphRunner* task_graph_runner,
                         ResourceProvider* resource_provider);
 
  private:
   void OnRasterFinished();
   void OnRasterRequiredForActivationFinished();
-  scoped_ptr<base::Value> StateAsValue() const;
+  scoped_refptr<base::debug::ConvertableToTraceFormat> StateAsValue() const;
 
   scoped_refptr<base::SequencedTaskRunner> task_runner_;
   TaskGraphRunner* task_graph_runner_;
   const NamespaceToken namespace_token_;
   RasterizerClient* client_;
   ResourceProvider* resource_provider_;
 
   bool raster_tasks_pending_;
   bool raster_tasks_required_for_activation_pending_;
 
   base::WeakPtrFactory<ImageRasterWorkerPool> raster_finished_weak_ptr_factory_;
 
   scoped_refptr<RasterizerTask> raster_finished_task_;
   scoped_refptr<RasterizerTask> raster_required_for_activation_finished_task_;
 
   // Task graph used when scheduling tasks and vector used to gather
   // completed tasks.
   TaskGraph graph_;
   Task::Vector completed_tasks_;
 
   DISALLOW_COPY_AND_ASSIGN(ImageRasterWorkerPool);
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_IMAGE_RASTER_WORKER_POOL_H_