Mozart: Improve internal scene graph representation.

services/gfx/compositor/render/render_frame.cc

 // 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 "services/gfx/compositor/render/render_frame.h"
 
 #include "base/logging.h"
-#include "services/gfx/compositor/render/render_layer.h"
 #include "skia/ext/refptr.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkPicture.h"
-#include "third_party/skia/include/core/SkPoint.h"
 
 namespace compositor {
 
-RenderFrame::RenderFrame(const std::shared_ptr<RenderLayer>& root_layer,
+RenderFrame::RenderFrame(const skia::RefPtr<SkPicture>& picture,
                          const SkRect& viewport,
                          const mojo::gfx::composition::FrameInfo& frame_info)
-    : root_layer_(root_layer), viewport_(viewport), frame_info_(frame_info) {
-  DCHECK(root_layer_);
+    : picture_(picture), viewport_(viewport), frame_info_(frame_info) {
+  DCHECK(picture_);
 }
 
 RenderFrame::~RenderFrame() {}
 
 void RenderFrame::Paint(SkCanvas* canvas) const {
+  DCHECK(canvas);
+
   // TODO: Consider using GrDrawContext instead of SkCanvas.
   canvas->clear(SK_ColorBLACK);
-  canvas->drawPicture(root_layer_->picture().get());
-  canvas->flush();
-}
-
-mojo::gfx::composition::HitTestResultPtr RenderFrame::HitTest(
-    const SkPoint& point) const {
-  // TODO: implement me
-  auto result = mojo::gfx::composition::HitTestResult::New();
-  result->hits.resize(0u);
-  return result.Pass();
+  canvas->drawPicture(picture_.get());
 }
 
 }  // namespace compositor