Split ExtensionMessageFilter up into a UI thread part and an IO thread part.

extensions/shell/browser/shell_content_browser_client.cc

 // Copyright 2014 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 "extensions/shell/browser/shell_content_browser_client.h"
 
 #include "base/command_line.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/site_instance.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/url_constants.h"
 #include "content/shell/browser/shell_browser_context.h"
 #include "content/shell/browser/shell_devtools_manager_delegate.h"
 #include "extensions/browser/extension_message_filter.h"
 #include "extensions/browser/extension_protocols.h"
 #include "extensions/browser/extension_registry.h"
 #include "extensions/browser/guest_view/guest_view_message_filter.h"
 #include "extensions/browser/info_map.h"
+#include "extensions/browser/io_thread_extension_message_filter.h"
 #include "extensions/browser/process_map.h"
 #include "extensions/common/constants.h"
 #include "extensions/common/extension.h"
 #include "extensions/common/switches.h"
 #include "extensions/shell/browser/shell_browser_context.h"
 #include "extensions/shell/browser/shell_browser_main_parts.h"
 #include "extensions/shell/browser/shell_extension_system.h"
 #include "extensions/shell/browser/shell_speech_recognition_manager_delegate.h"
 #include "url/gurl.h"
 
@@ skipping 45 matching lines @@
   return browser_main_parts_;
 }
 
 void ShellContentBrowserClient::RenderProcessWillLaunch(
     content::RenderProcessHost* host) {
   int render_process_id = host->GetID();
   BrowserContext* browser_context = browser_main_parts_->browser_context();
   host->AddFilter(
       new ExtensionMessageFilter(render_process_id, browser_context));
   host->AddFilter(
+      new IOThreadExtensionMessageFilter(render_process_id, browser_context));
+  host->AddFilter(
       new GuestViewMessageFilter(render_process_id, browser_context));
   // PluginInfoMessageFilter is not required because app_shell does not have
   // the concept of disabled plugins.
 #if !defined(DISABLE_NACL)
   host->AddFilter(new nacl::NaClHostMessageFilter(
       render_process_id,
       browser_context->IsOffTheRecord(),
       browser_context->GetPath(),
       browser_context->GetRequestContextForRenderProcess(render_process_id)));
 #endif
@@ skipping 162 matching lines @@
 
 const Extension* ShellContentBrowserClient::GetExtension(
     content::SiteInstance* site_instance) {
   ExtensionRegistry* registry =
       ExtensionRegistry::Get(site_instance->GetBrowserContext());
   return registry->enabled_extensions().GetExtensionOrAppByURL(
       site_instance->GetSiteURL());
 }
 
 }  // namespace extensions