Have content/ create and destroy its own threads.

content/shell/shell_browser_main.cc

 // Copyright (c) 2011 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 "content/shell/shell_browser_main.h"
 
 #include "base/message_loop.h"
 #include "base/threading/thread.h"
 #include "base/threading/thread_restrictions.h"
 #include "content/browser/browser_process_sub_thread.h"
@@ skipping 11 matching lines @@
 ShellBrowserMainParts::ShellBrowserMainParts(
     const content::MainFunctionParams& parameters)
     : BrowserMainParts() {
   ShellContentBrowserClient* shell_browser_client =
       static_cast<ShellContentBrowserClient*>(
           content::GetContentClient()->browser());
   shell_browser_client->set_shell_browser_main_parts(this);
 }
 
 ShellBrowserMainParts::~ShellBrowserMainParts() {
-  base::ThreadRestrictions::SetIOAllowed(true);
-    io_thread()->message_loop()->PostTask(
-        FROM_HERE,
-        NewRunnableFunction(&base::ThreadRestrictions::SetIOAllowed, true));
-
-  browser_context_.reset();
-
-  resource_dispatcher_host_->download_file_manager()->Shutdown();
-  resource_dispatcher_host_->save_file_manager()->Shutdown();
-  resource_dispatcher_host_->Shutdown();
-  io_thread_.reset();
-  cache_thread_.reset();
-  process_launcher_thread_.reset();
-  file_thread_.reset();
-  resource_dispatcher_host_.reset();  // Kills WebKit thread.
-  db_thread_.reset();
 }
 
-void ShellBrowserMainParts::PreMainMessageLoopRun() {
-  db_thread_.reset(new BrowserProcessSubThread(BrowserThread::DB));
-  db_thread_->Start();
-  file_thread_.reset(new BrowserProcessSubThread(BrowserThread::FILE));
-  file_thread_->Start();
-  process_launcher_thread_.reset(
-      new BrowserProcessSubThread(BrowserThread::PROCESS_LAUNCHER));
-  process_launcher_thread_->Start();
-
-  base::Thread::Options options;
-  options.message_loop_type = MessageLoop::TYPE_IO;
-
-  cache_thread_.reset(new BrowserProcessSubThread(BrowserThread::CACHE));
-  cache_thread_->StartWithOptions(options);
-  io_thread_.reset(new BrowserProcessSubThread(BrowserThread::IO));
-  io_thread_->StartWithOptions(options);
-
+content::IOThreadDelegate* ShellBrowserMainParts::PreMainMessageLoopRun() {
   browser_context_.reset(new ShellBrowserContext(this));
 
   Shell::PlatformInitialize();
   net::NetModule::SetResourceProvider(Shell::PlatformResourceProvider);
 
   Shell::CreateNewWindow(browser_context_.get(),
                          GURL("http://www.google.com"),
                          NULL,
                          MSG_ROUTING_NONE,
                          NULL);
+  return NULL;
+}
 
+void ShellBrowserMainParts::PostMainMessageLoopRun() {
+  browser_context_.reset();
+
+  resource_dispatcher_host_->download_file_manager()->Shutdown();
+  resource_dispatcher_host_->save_file_manager()->Shutdown();
+  resource_dispatcher_host_->Shutdown();
+}
+
+void ShellBrowserMainParts::PreStopThread(BrowserThread::ID id) {
+  if (id == BrowserThread::WEBKIT) {
+    // It remains the embedder's responsibility to kill the WebKit
+    // thread.  This happens when RDH is destroyed.
+    resource_dispatcher_host_.reset();
+  }
 }
 
 bool ShellBrowserMainParts::MainMessageLoopRun(int* result_code) {
   return false;
 }
 
 ResourceDispatcherHost* ShellBrowserMainParts::GetResourceDispatcherHost() {
   if (!resource_dispatcher_host_.get()) {
     ResourceQueue::DelegateSet resource_queue_delegates;
     resource_dispatcher_host_.reset(
         new ResourceDispatcherHost(resource_queue_delegates));
     resource_dispatcher_host_->Initialize();
   }
   return resource_dispatcher_host_.get();
 }
 
 ui::Clipboard* ShellBrowserMainParts::GetClipboard() {
   if (!clipboard_.get())
     clipboard_.reset(new ui::Clipboard());
   return clipboard_.get();
 }
 
 }  // namespace