cc:: Add RenderingStatsInstrumentation to manage collection of RenderingStats

cc/worker_pool.h

Index: cc/worker_pool.h
diff --git a/cc/worker_pool.h b/cc/worker_pool.h
index d6474e8541048068785d0f7cef7601551ae062cc..03b46effb0a84a90d9482ebc3501080b3aa2ffd0 100644
--- a/cc/worker_pool.h
+++ b/cc/worker_pool.h
@@ -15,7 +15,6 @@
 #include "cc/scoped_ptr_deque.h"
 
 namespace cc {
-struct RenderingStats;
 
 namespace internal {
 
@@ -28,7 +27,7 @@ class WorkerPoolTask {
   // Called before running the task on a thread that isn't the origin thread.
   virtual void WillRunOnThread(unsigned thread_index) = 0;
 
-  virtual void Run(RenderingStats* rendering_stats) = 0;
+  virtual void Run() = 0;
 
   void DidComplete();
 
@@ -52,7 +51,7 @@ class CC_EXPORT WorkerPoolClient {
 // of all pending tasks at shutdown.
 class WorkerPool {
  public:
-  typedef base::Callback<void(RenderingStats*)> Callback;
+  typedef base::Callback<void()> Callback;
 
   virtual ~WorkerPool();
 
@@ -78,12 +77,6 @@ class WorkerPool {
   // Set time limit for running cheap tasks.
   void SetRunCheapTasksTimeLimit(base::TimeTicks run_cheap_tasks_time_limit);
 
-  // Toggle rendering stats collection.
-  void SetRecordRenderingStats(bool record_rendering_stats);
-
-  // Collect rendering stats of all completed tasks.
-  void GetRenderingStats(RenderingStats* stats);
-
  protected:
   WorkerPool(WorkerPoolClient* client,
              size_t num_threads,