cc: Avoid expensive RenderingStats collection.

cc/bitmap_content_layer_updater.cc

 // 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.
 
 #include "cc/bitmap_content_layer_updater.h"
 
 #include "cc/layer_painter.h"
 #include "cc/prioritized_resource.h"
 #include "cc/rendering_stats.h"
 #include "cc/resource_update.h"
 #include "cc/resource_update_queue.h"
 #include "skia/ext/platform_canvas.h"
 
 namespace cc {
 
 BitmapContentLayerUpdater::Resource::Resource(BitmapContentLayerUpdater* updater, scoped_ptr<PrioritizedResource> texture)
     : LayerUpdater::Resource(texture.Pass())
     , m_updater(updater)
 {
 }
 
 BitmapContentLayerUpdater::Resource::~Resource()
 {
 }
 
-void BitmapContentLayerUpdater::Resource::update(ResourceUpdateQueue& queue, const gfx::Rect& sourceRect, const gfx::Vector2d& destOffset, bool partialUpdate, RenderingStats&)
+void BitmapContentLayerUpdater::Resource::update(ResourceUpdateQueue& queue, const gfx::Rect& sourceRect, const gfx::Vector2d& destOffset, bool partialUpdate, RenderingStats*)
 {
     updater()->updateTexture(queue, texture(), sourceRect, destOffset, partialUpdate);
 }
 
 scoped_refptr<BitmapContentLayerUpdater> BitmapContentLayerUpdater::create(scoped_ptr<LayerPainter> painter)
 {
     return make_scoped_refptr(new BitmapContentLayerUpdater(painter.Pass()));
 }
 
 BitmapContentLayerUpdater::BitmapContentLayerUpdater(scoped_ptr<LayerPainter> painter)
     : ContentLayerUpdater(painter.Pass())
     , m_opaque(false)
 {
 }
 
 BitmapContentLayerUpdater::~BitmapContentLayerUpdater()
 {
 }
 
 scoped_ptr<LayerUpdater::Resource> BitmapContentLayerUpdater::createResource(PrioritizedResourceManager* manager)
 {
     return scoped_ptr<LayerUpdater::Resource>(new Resource(this, PrioritizedResource::create(manager)));
 }
 
-void BitmapContentLayerUpdater::prepareToUpdate(const gfx::Rect& contentRect, const gfx::Size& tileSize, float contentsWidthScale, float contentsHeightScale, gfx::Rect& resultingOpaqueRect, RenderingStats& stats)
+void BitmapContentLayerUpdater::prepareToUpdate(const gfx::Rect& contentRect, const gfx::Size& tileSize, float contentsWidthScale, float contentsHeightScale, gfx::Rect& resultingOpaqueRect, RenderingStats* stats)
 {
     if (m_canvasSize != contentRect.size()) {
         m_canvasSize = contentRect.size();
         m_canvas = make_scoped_ptr(skia::CreateBitmapCanvas(m_canvasSize.width(), m_canvasSize.height(), m_opaque));
     }
 
-    stats.totalPixelsRasterized += contentRect.width() * contentRect.height();
+    if (stats)
+      stats->totalPixelsRasterized += contentRect.width() * contentRect.height();
 
     paintContents(m_canvas.get(), contentRect, contentsWidthScale, contentsHeightScale, resultingOpaqueRect, stats);
 }
 
 void BitmapContentLayerUpdater::updateTexture(ResourceUpdateQueue& queue, PrioritizedResource* texture, const gfx::Rect& sourceRect, const gfx::Vector2d& destOffset, bool partialUpdate)
 {
     ResourceUpdate upload = ResourceUpdate::Create(
         texture,
         &m_canvas->getDevice()->accessBitmap(false),
         contentRect(),
         sourceRect,
         destOffset);
     if (partialUpdate)
         queue.appendPartialUpload(upload);
     else
         queue.appendFullUpload(upload);
 }
 
 void BitmapContentLayerUpdater::setOpaque(bool opaque)
 {
     if (opaque != m_opaque) {
         m_canvas.reset();
         m_canvasSize = gfx::Size();
     }
     m_opaque = opaque;
 }
 
 }  // namespace cc