Teach SkyShell how to draw with Ganesh

sky/shell/gpu/rasterizer.cc

Index: sky/shell/gpu/rasterizer.cc
diff --git a/sky/shell/gpu/rasterizer.cc b/sky/shell/gpu/rasterizer.cc
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index 0000000000000000000000000000000000000000..8e4b49282e31b5a8160008d093aaa46b117bae0b
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+++ b/sky/shell/gpu/rasterizer.cc
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+// 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/rasterizer.h"
+
+#include "sky/shell/gpu/ganesh_context.h"
+#include "sky/shell/gpu/ganesh_surface.h"
+#include "third_party/skia/include/core/SkCanvas.h"
+#include "third_party/skia/include/core/SkPicture.h"
+#include "ui/gl/gl_bindings.h"
+#include "ui/gl/gl_context.h"
+#include "ui/gl/gl_share_group.h"
+#include "ui/gl/gl_surface.h"
+
+namespace sky {
+namespace shell {
+namespace {
+
+gfx::Size GetSize(SkPicture* picture) {
+  const SkRect& rect = picture->cullRect();
+  return gfx::Size(rect.width(), rect.height());
+}
+
+}  // namespace
+
+Rasterizer::Rasterizer() : weak_factory_(this) {
+}
+
+Rasterizer::~Rasterizer() {
+}
+
+base::WeakPtr<Rasterizer> Rasterizer::GetWeakPtr() {
+  return weak_factory_.GetWeakPtr();
+}
+
+void Rasterizer::Init(gfx::AcceleratedWidget widget) {
+  share_group_ = make_scoped_refptr(new gfx::GLShareGroup());
+  surface_ = gfx::GLSurface::CreateViewGLSurface(widget);
+  CHECK(surface_) << "GLSurface required.";
+  CHECK(CreateGLContext()) << "GLContext required.";
+}
+
+void Rasterizer::Draw(skia::RefPtr<SkPicture> picture) {
+  // TODO(abarth): We should handle losing the GL context.
+  CHECK(context_->MakeCurrent(surface_.get()));
+  EnsureGaneshSurface(GetSize(picture.get()));
+
+  SkCanvas* canvas = ganesh_surface_->canvas();
+  canvas->drawPicture(picture.get());
+  canvas->flush();
+
+  surface_->SwapBuffers();
+}
+
+bool Rasterizer::CreateGLContext() {
+  context_ = gfx::GLContext::CreateGLContext(share_group_.get(), surface_.get(),
+                                             gfx::PreferIntegratedGpu);
+  if (!context_)
+    return false;
+  ganesh_context_.reset(new GaneshContext(context_.get()));
+  return true;
+}
+
+void Rasterizer::EnsureGaneshSurface(const gfx::Size& size) {
+  if (!ganesh_surface_ || ganesh_surface_->size() != size)
+    ganesh_surface_.reset(new GaneshSurface(ganesh_context_.get(), size));
+}
+
+}  // namespace shell
+}  // namespace sky