Add APIs for dynamic display lists, using SkDrawable and SkPictureRecorder::endRecordingAsDrawable.

sky/engine/core/painting/PictureRecorder.cpp

 // Copyright 2015 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 "sky/engine/core/painting/Canvas.h"
+#include "sky/engine/core/painting/Drawable.h"
 #include "sky/engine/core/painting/Picture.h"
 #include "sky/engine/core/painting/PictureRecorder.h"
 
 namespace blink {
 
 PictureRecorder::PictureRecorder()
     : m_pictureRecorder(adoptPtr(new SkPictureRecorder()))
 {
 }
 
@@ skipping 14 matching lines @@
 {
     if (!isRecording())
         return nullptr;
     RefPtr<Picture> picture = Picture::create(
         adoptRef(m_pictureRecorder->endRecording()));
     m_canvas->clearSkCanvas();
     m_canvas = nullptr;
     return picture.release();
 }
 
+PassRefPtr<Drawable> PictureRecorder::endRecordingAsDrawable()
+{
+    if (!isRecording())
+        return nullptr;
+    RefPtr<Drawable> drawable = Drawable::create(
+        adoptRef(m_pictureRecorder->endRecordingAsDrawable()));
+    m_canvas->clearSkCanvas();
+    m_canvas = nullptr;
+    return drawable.release();
+}
+
 void PictureRecorder::set_canvas(PassRefPtr<Canvas> canvas) { m_canvas = canvas; }
 
 } // namespace blink