Back button should be able to close apps

sky/shell/shell_view.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_view.h"
 
 #include "base/bind.h"
 #include "base/single_thread_task_runner.h"
 #include "sky/shell/gpu/rasterizer.h"
 #include "sky/shell/platform_view.h"
 #include "sky/shell/shell.h"
 #include "sky/shell/ui/engine.h"
 
 namespace sky {
 namespace shell {
+namespace {
+
+template<typename T>
+void Drop(scoped_ptr<T> ptr) { }
+
+}  // namespace
 
 ShellView::ShellView(Shell& shell)
     : shell_(shell) {
   rasterizer_.reset(new Rasterizer());
   CreateEngine();
   CreatePlatformView();
 }
 
 ShellView::~ShellView() {
+  shell_.gpu_task_runner()->PostTask(FROM_HERE,
+      base::Bind(&Drop<Rasterizer>, base::Passed(&rasterizer_)));
+  shell_.ui_task_runner()->PostTask(FROM_HERE,
+      base::Bind(&Drop<Engine>, base::Passed(&engine_)));
 }
 
 void ShellView::CreateEngine() {
   Engine::Config config;
   config.service_provider_context = shell_.service_provider_context();
   config.gpu_task_runner = shell_.gpu_task_runner();
   config.gpu_delegate = rasterizer_->GetWeakPtr();
   engine_.reset(new Engine(config));
 }
 
 void ShellView::CreatePlatformView() {
   PlatformView::Config config;
   config.ui_task_runner = shell_.ui_task_runner();
   config.ui_delegate = engine_->GetWeakPtr();
   view_.reset(PlatformView::Create(config));
 }
 
 }  // namespace shell
 }  // namespace sky