Sky should use an SkPicture when drawing

sky/compositor/rasterizer_ganesh.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 "sky/compositor/rasterizer_ganesh.h"
+
+#include "base/debug/trace_event.h"
+#include "mojo/skia/ganesh_surface.h"
+#include "sky/compositor/layer_host.h"
+#include "third_party/skia/include/core/SkCanvas.h"
+#include "third_party/skia/include/core/SkPicture.h"
+
+namespace sky {
+
+RasterizerGanesh::RasterizerGanesh(LayerHost* host) : host_(host) {
+  DCHECK(host_);
+}
+
+RasterizerGanesh::~RasterizerGanesh() {
+}
+
+scoped_ptr<mojo::GLTexture> RasterizerGanesh::Rasterize(SkPicture* picture) {
+  TRACE_EVENT0("sky", "RasterizerGanesh::Rasterize");
+
+  SkRect cull_rect = picture->cullRect();
+  gfx::Size size(cull_rect.width(), cull_rect.height());
+
+  mojo::GaneshSurface surface(host_->ganesh_context(),
+                              host_->resource_manager()->CreateTexture(size));
+
+  SkCanvas* canvas = surface.canvas();
+  canvas->drawPicture(picture);
+  canvas->flush();
+
+  return surface.TakeTexture();
+}
+
+}  // namespace sky