Use the skmultipicture to perform GPU rasterization

cc/resources/picture.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/picture.h"
 
 #include <algorithm>
 #include <limits>
 #include <set>
 
@@ skipping 332 matching lines @@
 
   canvas->save();
 
   for (Region::Iterator it(negated_content_region); it.has_rect(); it.next())
     canvas->clipRect(gfx::RectToSkRect(it.rect()), SkRegion::kDifference_Op);
 
   canvas->scale(contents_scale, contents_scale);
   canvas->translate(layer_rect_.x(), layer_rect_.y());
   if (playback_) {
     playback_->draw(canvas);
+  } else if (callback) {
+    // If we have a callback, we need to call |draw()|, |drawPicture()| doesn't
+    // take a callback.  This is used by |AnalysisCanvas| to early out.
+    picture_->draw(canvas, callback);
   } else {
-    picture_->draw(canvas, callback);
+    // Prefer to call |drawPicture()| on the canvas since it could place the
+    // entire picture on the canvas instead of parsing the skia operations.
+    canvas->drawPicture(picture_.get());
   }
   SkIRect bounds;
   canvas->getClipDeviceBounds(&bounds);
   canvas->restore();
   TRACE_EVENT_END1(
       "cc", "Picture::Raster",
       "num_pixels_rasterized", bounds.width() * bounds.height());
   return bounds.width() * bounds.height();
 }
 
@@ skipping 176 matching lines @@
   scoped_refptr<base::debug::TracedValue> record_data =
       new base::debug::TracedValue();
   TracedValue::SetIDRef(this, record_data.get(), "picture_id");
   record_data->BeginArray("layer_rect");
   MathUtil::AddToTracedValue(layer_rect_, record_data.get());
   record_data->EndArray();
   return record_data;
 }
 
 }  // namespace cc