cc: Avoid expensive RenderingStats collection.

cc/bitmap_skpicture_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_skpicture_content_layer_updater.h"
 
 #include "base/time.h"
 #include "cc/layer_painter.h"
 #include "cc/prioritized_resource.h"
 #include "cc/rendering_stats.h"
 #include "cc/resource_update_queue.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkDevice.h"
 
 namespace cc {
 
 BitmapSkPictureContentLayerUpdater::Resource::Resource(BitmapSkPictureContentLayerUpdater* updater, scoped_ptr<PrioritizedResource> texture)
     : ContentLayerUpdater::Resource(texture.Pass())
     , m_updater(updater)
 {
 }
 
-void BitmapSkPictureContentLayerUpdater::Resource::update(ResourceUpdateQueue& queue, const gfx::Rect& sourceRect, const gfx::Vector2d& destOffset, bool partialUpdate, RenderingStats& stats)
+void BitmapSkPictureContentLayerUpdater::Resource::update(ResourceUpdateQueue& queue, const gfx::Rect& sourceRect, const gfx::Vector2d& destOffset, bool partialUpdate, RenderingStats* stats)
 {
     m_bitmap.setConfig(SkBitmap::kARGB_8888_Config, sourceRect.width(), sourceRect.height());
     m_bitmap.allocPixels();
     m_bitmap.setIsOpaque(m_updater->layerIsOpaque());
     SkDevice device(m_bitmap);
     SkCanvas canvas(&device);
-    base::TimeTicks paintBeginTime = base::TimeTicks::Now();
+    base::TimeTicks paintBeginTime;
+    if (stats)
+      paintBeginTime = base::TimeTicks::Now();
     updater()->paintContentsRect(&canvas, sourceRect, stats);
-    stats.totalPaintTime += base::TimeTicks::Now() - paintBeginTime;
+    if (stats)
+      stats->totalPaintTime += base::TimeTicks::Now() - paintBeginTime;
 
     ResourceUpdate upload = ResourceUpdate::Create(
         texture(), &m_bitmap, sourceRect, sourceRect, destOffset);
     if (partialUpdate)
         queue.appendPartialUpload(upload);
     else
         queue.appendFullUpload(upload);
 }
 
 scoped_refptr<BitmapSkPictureContentLayerUpdater> BitmapSkPictureContentLayerUpdater::create(scoped_ptr<LayerPainter> painter)
 {
     return make_scoped_refptr(new BitmapSkPictureContentLayerUpdater(painter.Pass()));
 }
 
 BitmapSkPictureContentLayerUpdater::BitmapSkPictureContentLayerUpdater(scoped_ptr<LayerPainter> painter)
     : SkPictureContentLayerUpdater(painter.Pass())
 {
 }
 
 BitmapSkPictureContentLayerUpdater::~BitmapSkPictureContentLayerUpdater()
 {
 }
 
 scoped_ptr<LayerUpdater::Resource> BitmapSkPictureContentLayerUpdater::createResource(PrioritizedResourceManager* manager)
 {
     return scoped_ptr<LayerUpdater::Resource>(new Resource(this, PrioritizedResource::create(manager)));
 }
 
-void BitmapSkPictureContentLayerUpdater::paintContentsRect(SkCanvas* canvas, const gfx::Rect& sourceRect, RenderingStats& stats)
+void BitmapSkPictureContentLayerUpdater::paintContentsRect(SkCanvas* canvas, const gfx::Rect& sourceRect, RenderingStats* stats)
 {
     // Translate the origin of contentRect to that of sourceRect.
     canvas->translate(contentRect().x() - sourceRect.x(),
                       contentRect().y() - sourceRect.y());
-    base::TimeTicks rasterizeBeginTime = base::TimeTicks::Now();
+    base::TimeTicks rasterizeBeginTime;
+    if (stats)
+      rasterizeBeginTime = base::TimeTicks::Now();
     drawPicture(canvas);
-    stats.totalRasterizeTime += base::TimeTicks::Now() - rasterizeBeginTime;
-    stats.totalPixelsRasterized += sourceRect.width() * sourceRect.height();
+    if (stats) {
+      stats->totalRasterizeTime += base::TimeTicks::Now() - rasterizeBeginTime;
+      stats->totalPixelsRasterized += sourceRect.width() * sourceRect.height();
+    }
 }
 
 }  // namespace cc