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

cc/resources/tile_manager.cc

Index: cc/resources/tile_manager.cc
diff --git a/cc/resources/tile_manager.cc b/cc/resources/tile_manager.cc
index 452d9b45ccfa5e65bdc444bdb3c3f36cc616f429..8e97c2024737ca266480b9a0757b6a05a170815a 100644
--- a/cc/resources/tile_manager.cc
+++ b/cc/resources/tile_manager.cc
@@ -93,6 +93,7 @@ class RasterTaskImpl : public RasterTask {
   void AnalyzeAndRaster(PicturePileImpl* picture_pile) {
     DCHECK(picture_pile);
     DCHECK(canvas_);
+    DCHECK(canvas_->GetSkCanvas());
 
     if (analyze_picture_) {
       Analyze(picture_pile);
@@ -101,6 +102,8 @@ class RasterTaskImpl : public RasterTask {
     }
 
     Raster(picture_pile);
+
+    canvas_->Flush();
   }
 
   void Analyze(PicturePileImpl* picture_pile) {
@@ -141,7 +144,7 @@ class RasterTaskImpl : public RasterTask {
       default:
         NOTREACHED();
     }
-    canvas_->setDrawFilter(draw_filter.get());
+    canvas_->GetSkCanvas()->setDrawFilter(draw_filter.get());
 
     base::TimeDelta prev_rasterize_time =
         rendering_stats_->impl_thread_rendering_stats().rasterize_time;
@@ -154,7 +157,7 @@ class RasterTaskImpl : public RasterTask {
         tile_resolution_ == HIGH_RESOLUTION ? rendering_stats_ : NULL;
     DCHECK(picture_pile);
     picture_pile->RasterToBitmap(
-        canvas_, content_rect_, contents_scale_, stats);
+        canvas_->GetSkCanvas(), content_rect_, contents_scale_, stats);
 
     if (rendering_stats_->record_rendering_stats()) {
       base::TimeDelta current_rasterize_time =
@@ -180,7 +183,7 @@ class RasterTaskImpl : public RasterTask {
   bool analyze_picture_;
   RenderingStatsInstrumentation* rendering_stats_;
   const base::Callback<void(const PicturePileImpl::Analysis&, bool)> reply_;
-  SkCanvas* canvas_;
+  RasterCanvas* canvas_;
 
   DISALLOW_COPY_AND_ASSIGN(RasterTaskImpl);
 };