cc: Avoid expensive RenderingStats collection.

cc/raster_worker_pool.h

Index: cc/raster_worker_pool.h
diff --git a/cc/raster_worker_pool.h b/cc/raster_worker_pool.h
index e4073129a8c84002c36114a18912e30e5bfec43b..027c434a7bd7497cdc97c91f2e899ff2d968cc87 100644
--- a/cc/raster_worker_pool.h
+++ b/cc/raster_worker_pool.h
@@ -22,11 +22,12 @@ class PicturePileImpl;
 
 class RasterWorkerPool {
  public:
-  explicit RasterWorkerPool(size_t num_raster_threads);
   virtual ~RasterWorkerPool();
 
-  static scoped_ptr<RasterWorkerPool> Create(size_t num_raster_threads) {
-    return make_scoped_ptr(new RasterWorkerPool(num_raster_threads));
+  static scoped_ptr<RasterWorkerPool> Create(
+      size_t num_raster_threads, bool record_rendering_stats) {
+    return make_scoped_ptr(new RasterWorkerPool(
+        num_raster_threads, record_rendering_stats));
   }
 
   // Starts the worker pool. Returns true if the worker pool was successfully
@@ -53,6 +54,8 @@ class RasterWorkerPool {
   void GetRenderingStats(RenderingStats* stats);
 
  private:
+  RasterWorkerPool(size_t num_raster_threads, bool record_rendering_stats);
+
   class Thread : public base::Thread {
    public:
     class Task {
@@ -107,6 +110,7 @@ class RasterWorkerPool {
   typedef std::vector<Thread*> ThreadVector;
   ThreadVector raster_threads_;
   bool raster_threads_need_sorting_;
+  bool record_rendering_stats_;
 
   DISALLOW_COPY_AND_ASSIGN(RasterWorkerPool);
 };