cc: Do bitmap conversion for RasterBuffer in the worker thread.

cc/resources/tile_manager.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/resources/tile_manager.h"
 
 #include <algorithm>
 #include <limits>
 #include <string>
 
@@ skipping 112 matching lines @@
   void Raster(PicturePileImpl* picture_pile) {
     frame_viewer_instrumentation::ScopedRasterTask raster_task(
         tile_id_,
         tile_resolution_,
         source_frame_number_,
         layer_id_,
         raster_mode_);
     devtools_instrumentation::ScopedLayerTask layer_task(
         devtools_instrumentation::kRasterTask, layer_id_);
 
-    SkCanvas* canvas = raster_buffer_->AcquireSkCanvas();
+    skia::RefPtr<SkCanvas> canvas = raster_buffer_->AcquireSkCanvas();
     DCHECK(canvas);
 
     skia::RefPtr<SkDrawFilter> draw_filter;
     switch (raster_mode_) {
       case LOW_QUALITY_RASTER_MODE:
         draw_filter = skia::AdoptRef(new skia::PaintSimplifier);
         break;
       case HIGH_QUALITY_RASTER_MODE:
         break;
       case NUM_RASTER_MODES:
       default:
         NOTREACHED();
     }
     canvas->setDrawFilter(draw_filter.get());
 
     base::TimeDelta prev_rasterize_time =
         rendering_stats_->impl_thread_rendering_stats().rasterize_time;
 
     // Only record rasterization time for highres tiles, because
     // lowres tiles are not required for activation and therefore
     // introduce noise in the measurement (sometimes they get rasterized
     // before we draw and sometimes they aren't)
     RenderingStatsInstrumentation* stats =
         tile_resolution_ == HIGH_RESOLUTION ? rendering_stats_ : NULL;
     DCHECK(picture_pile);
-    picture_pile->RasterToBitmap(canvas, content_rect_, contents_scale_, stats);
+    picture_pile->RasterToBitmap(
+        canvas.get(), content_rect_, contents_scale_, stats);
 
     if (rendering_stats_->record_rendering_stats()) {
       base::TimeDelta current_rasterize_time =
           rendering_stats_->impl_thread_rendering_stats().rasterize_time;
       HISTOGRAM_CUSTOM_COUNTS(
           "Renderer4.PictureRasterTimeUS",
           (current_rasterize_time - prev_rasterize_time).InMicroseconds(),
           0,
           100000,
           100);
     }
 
-    raster_buffer_->ReleaseSkCanvas();
+    bool content_has_changed = raster_buffer_->ReleaseSkCanvas(canvas.get());
+    set_content_has_changed(content_has_changed);
   }
 
   PicturePileImpl::Analysis analysis_;
   scoped_refptr<PicturePileImpl> picture_pile_;
   gfx::Rect content_rect_;
   float contents_scale_;
   RasterMode raster_mode_;
   TileResolution tile_resolution_;
   int layer_id_;
   const void* tile_id_;
@@ skipping 1002 matching lines @@
   TRACE_EVENT0("cc", "TileManager::CheckIfReadyToActivate");
 
   rasterizer_->CheckForCompletedTasks();
   did_check_for_completed_tasks_since_last_schedule_tasks_ = true;
 
   if (IsReadyToActivate())
     client_->NotifyReadyToActivate();
 }
 
 }  // namespace cc