Add a skeleton Start Page to the experimental app list.

ui/app_list/app_list_switches.cc

 // Copyright 2013 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 "ui/app_list/app_list_switches.h"
 
 #include "base/command_line.h"
 
 namespace app_list {
 namespace switches {
 
 // If set, the experimental app list will be used.
 const char kEnableExperimentalAppList[] = "enable-experimental-app-list";
 
 // If set, folder will be enabled in app list UI.
 const char kEnableFolderUI[] = "enable-app-list-folder-ui";
 
 // If set, the voice search is disabled in app list UI.
 const char kDisableVoiceSearch[] = "disable-app-list-voice-search";
 
 // If set, the app info context menu item is available in the app list UI.
 const char kEnableAppInfo[] = "enable-app-list-app-info";
 
+// If set, the app list will show the start page webui.
+const char kShowAppListStartPage[] = "show-app-list-start-page";
+
 bool IsFolderUIEnabled() {
   return CommandLine::ForCurrentProcess()->HasSwitch(kEnableFolderUI);
 }
 
 bool IsVoiceSearchEnabled() {
   // Speech recognition in AppList is only for ChromeOS right now.
 #if defined(OS_CHROMEOS)
   return !CommandLine::ForCurrentProcess()->HasSwitch(kDisableVoiceSearch);
 #else
   return false;
 #endif
 }
 
 bool IsAppInfoEnabled() {
   return CommandLine::ForCurrentProcess()->HasSwitch(kEnableAppInfo);
 }
 
 bool IsExperimentalAppListEnabled() {
   return CommandLine::ForCurrentProcess()->HasSwitch(
       kEnableExperimentalAppList);
 }
 
+bool IsStartPageWebUIEnabled() {
+  return CommandLine::ForCurrentProcess()->HasSwitch(kShowAppListStartPage);
+}
+
 }  // namespace switches
 }  // namespace app_list