Teach SkyShell how to draw with Ganesh

sky/shell/gpu/ganesh_surface.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/shell/gpu/ganesh_surface.h"
+
+#include "third_party/skia/include/gpu/GrContext.h"
+
+namespace sky {
+namespace shell {
+
+GaneshSurface::GaneshSurface(GaneshContext* context, const gfx::Size& size) {
+  GrBackendRenderTargetDesc desc;
+  desc.fWidth = size.width();
+  desc.fHeight = size.height();
+  desc.fConfig = kSkia8888_GrPixelConfig;
+  desc.fOrigin = kTopLeft_GrSurfaceOrigin;
+
+  auto target = skia::AdoptRef(context->gr()->wrapBackendRenderTarget(desc));
+  DCHECK(target);
+  surface_ = skia::AdoptRef(SkSurface::NewRenderTargetDirect(target.get()));
+  DCHECK(surface_);
+}
+
+GaneshSurface::~GaneshSurface() {
+}
+
+}  // namespace shell
+}  // namespace sky