cc: Avoid expensive RenderingStats collection.

cc/picture_layer.cc

 // 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.
 
 #include "cc/picture_layer.h"
 
 #include "cc/layer_tree_impl.h"
 #include "cc/picture_layer_impl.h"
 #include "ui/gfx/rect_conversions.h"
 
@@ skipping 43 matching lines @@
   gfx::Rect rect = gfx::ToEnclosedRect(layer_rect);
   if (!rect.IsEmpty()) {
     // Clamp invalidation to the layer bounds.
     rect.Intersect(gfx::Rect(bounds()));
     pending_invalidation_.Union(rect);
   }
   Layer::setNeedsDisplayRect(layer_rect);
 }
 
 void PictureLayer::update(ResourceUpdateQueue&, const OcclusionTracker*,
-                    RenderingStats& stats) {
+                          RenderingStats* stats) {
   // Do not early-out of this function so that PicturePile::Update has a chance
   // to record pictures due to changing visibility of this layer.
 
   pile_->Resize(bounds());
 
   // Calling paint in WebKit can sometimes cause invalidations, so save
   // off the invalidation prior to calling update.
   pile_invalidation_.Swap(pending_invalidation_);
   pending_invalidation_.Clear();
 
   gfx::Rect visible_layer_rect = gfx::ToEnclosingRect(
       gfx::ScaleRect(visibleContentRect(), 1.f / contentsScaleX()));
   pile_->Update(client_, pile_invalidation_, visible_layer_rect, stats);
 }
 
 void PictureLayer::setIsMask(bool is_mask) {
   is_mask_ = is_mask;
 }
 
 }  // namespace cc