Have content/ create and destroy its own threads.

content/browser/renderer_host/render_view_host.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/browser/renderer_host/render_view_host.h"
 
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/i18n/rtl.h"
 #include "base/json/json_reader.h"
+#include "base/message_loop.h"
 #include "base/stl_util.h"
 #include "base/string_util.h"
 #include "base/time.h"
 #include "base/utf_string_conversions.h"
 #include "base/values.h"
 #include "content/browser/browser_context.h"
 #include "content/browser/browser_message_filter.h"
 #include "content/browser/child_process_security_policy.h"
 #include "content/browser/cross_site_request_manager.h"
 #include "content/browser/host_zoom_map.h"
@@ skipping 1474 matching lines @@
 
 void RenderViewHost::OnWebUISend(const GURL& source_url,
                                  const std::string& name,
                                  const base::ListValue& args) {
   delegate_->WebUISend(this, source_url, name, args);
 }
 
 void RenderViewHost::ClearPowerSaveBlockers() {
   STLDeleteValues(&power_save_blockers_);
 }