sky/shell should link with sky/engine

sky/shell/shell.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/shell.h"
 
 #include "base/bind.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread.h"
 #include "sky/shell/sky_view.h"
 
 namespace sky {
 namespace shell {
 
 Shell::Shell(scoped_refptr<base::SingleThreadTaskRunner> java_task_runner)
     : java_task_runner_(java_task_runner) {
 }
 
 Shell::~Shell() {
 }
 
 void Shell::Init() {
   gpu_thread_.reset(new base::Thread("gpu_thread"));
   gpu_thread_->Start();
   rasterizer_.reset(new Rasterizer());
 
+  ui_thread_.reset(new base::Thread("ui_thread"));
+  ui_thread_->Start();
+  engine_.reset(new Engine());
+
+  ui_thread_->message_loop()->PostTask(
+      FROM_HERE, base::Bind(&Engine::Init, engine_->GetWeakPtr()));
+
   view_.reset(new SkyView(this));
   view_->Init();
 }
 
 void Shell::OnAcceleratedWidgetAvailable(gfx::AcceleratedWidget widget) {
   gpu_thread_->message_loop()->PostTask(
       FROM_HERE,
       base::Bind(&Rasterizer::Init, rasterizer_->GetWeakPtr(), widget));
 }
 
 void Shell::OnDestroyed() {
 }
 
 }  // namespace shell
 }  // namespace sky