Handle extension webrequest API on the IO thread. This speeds up blocking event

chrome/browser/ui/panels/panel_browser_view_browsertest.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 "base/command_line.h"
 #include "base/i18n/time_formatting.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_window.h"
@@ skipping 197 matching lines @@
     if (!options_page.empty()) {
       input_value.SetString(extension_manifest_keys::kOptionsPage,
                             options_page);
     }
     std::string error;
     scoped_refptr<Extension> extension = Extension::Create(
         full_path, location, input_value, Extension::STRICT_ERROR_CHECKS,
         &error);
     ASSERT_TRUE(extension.get());
     EXPECT_STREQ("", error.c_str());
-    browser()->GetProfile()->GetExtensionService()->AddExtension(
+    browser()->GetProfile()->GetExtensionService()->OnLoadSingleExtension(
         extension.get());
 
-    // Makes sure that async task ExtensionPrefs::OnExtensionInstalled gets a
-    // chance to be procesed.
-    MessageLoop::current()->RunAllPending();
-
     // Creates a panel with the app name that comes from the extension ID.
     PanelBrowserView* browser_view = CreatePanelBrowserView(
         web_app::GenerateApplicationNameFromExtensionId(extension->id()));
     PanelBrowserFrameView* frame_view = browser_view->GetFrameView();
 
     frame_view->EnsureSettingsMenuCreated();
     ASSERT_TRUE(frame_view->settings_menu_.get());
     ASSERT_TRUE(frame_view->settings_menu_contents_.get());
 
     // Validates the settings menu items.
@@ skipping 324 matching lines @@
 
 IN_PROC_BROWSER_TEST_F(PanelBrowserViewTest, CreateSettingsMenu) {
   TestCreateSettingsMenuForExtension(
       FILE_PATH_LITERAL("extension1"), Extension::EXTERNAL_POLICY_DOWNLOAD,
       "", "");
   TestCreateSettingsMenuForExtension(
       FILE_PATH_LITERAL("extension2"), Extension::INVALID,
       "http://home", "options.html");
 }
 #endif