Switching Chromium to use new Skia SkPictureRecorder API

cc/resources/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/resources/skpicture_content_layer_updater.h"
 
 #include "base/debug/trace_event.h"
 #include "cc/debug/rendering_stats_instrumentation.h"
 #include "cc/resources/layer_painter.h"
 #include "cc/resources/prioritized_resource.h"
 #include "cc/resources/resource_update_queue.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 
 namespace cc {
 
 SkPictureContentLayerUpdater::SkPictureContentLayerUpdater(
     scoped_ptr<LayerPainter> painter,
     RenderingStatsInstrumentation* stats_instrumentation,
     int layer_id)
     : ContentLayerUpdater(painter.Pass(), stats_instrumentation, layer_id) {}
 
 SkPictureContentLayerUpdater::~SkPictureContentLayerUpdater() {}
 
 void SkPictureContentLayerUpdater::PrepareToUpdate(
     const gfx::Rect& content_rect,
     const gfx::Size&,
     float contents_width_scale,
     float contents_height_scale,
     gfx::Rect* resulting_opaque_rect) {
-  SkCanvas* canvas =
-      picture_.beginRecording(content_rect.width(), content_rect.height());
+  SkCanvas* canvas = picture_recorder_.beginRecording(content_rect.width(),

[reed1, 2014/04/14 15:19:02]

Why does picture_recorder_ have to be a persistent object, instead of just on
the stack?

[robertphillips, 2014/04/14 15:36:28]

Done.

+                                                      content_rect.height());
   DCHECK_EQ(content_rect.width(), canvas->getBaseLayerSize().width());
   DCHECK_EQ(content_rect.height(), canvas->getBaseLayerSize().height());
   base::TimeTicks start_time =
       rendering_stats_instrumentation_->StartRecording();
   PaintContents(canvas,
                 content_rect,
                 contents_width_scale,
                 contents_height_scale,
                 resulting_opaque_rect);
   base::TimeDelta duration =
       rendering_stats_instrumentation_->EndRecording(start_time);
   rendering_stats_instrumentation_->AddRecord(
       duration, content_rect.width() * content_rect.height());
-  picture_.endRecording();
+  picture_ = skia::AdoptRef(picture_recorder_.endRecording());
 }
 
 void SkPictureContentLayerUpdater::DrawPicture(SkCanvas* canvas) {
   TRACE_EVENT0("cc", "SkPictureContentLayerUpdater::DrawPicture");
-  canvas->drawPicture(picture_);
+  if (picture_)
+    canvas->drawPicture(*picture_);
 }
 
 }  // namespace cc