Add a skeleton Start Page to the experimental app list.

chrome/browser/ui/app_list/start_page_service.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 "chrome/browser/ui/app_list/start_page_service.h"
 
 #include <string>
 
 #include "base/command_line.h"
 #include "base/memory/singleton.h"
@@ skipping 126 matching lines @@
   observers_.RemoveObserver(observer);
 }
 
 void StartPageService::ToggleSpeechRecognition() {
   speech_button_toggled_manually_ = true;
   contents_->GetWebUI()->CallJavascriptFunction(
       "appList.startPage.toggleSpeechRecognition");
 }
 
 content::WebContents* StartPageService::GetStartPageContents() {
-  return CommandLine::ForCurrentProcess()->HasSwitch(
-      ::switches::kShowAppListStartPage) ? contents_.get() : NULL;
+  return (app_list::switches::IsExperimentalAppListEnabled() ||
+      app_list::switches::IsExperimentalAppListEnabled()) ? contents_.get()

[tapted, 2014/03/10 02:41:54]

Do you still need to handle the "old" start page flag here? (or is it
deprecated? can the flags be folded in to each other?).

Reading more of the patch.. I actually think we need a separate function --
StartPageService::GetSearchPageContents -- and it should not be passed to the
AppsGridView constructor

[calamity, 2014/03/14 07:50:02]

xiyuan@ said that he's fine with changing the start page webui and having it
only be used for the experimental app launcher. However, we're not sure what the
responsibilities the webui will have yet (at the moment, the only thing I'm
using it for is a web surface to have a logo, hopefully allowing us to hook into
the instant extended stuff).

I think we can remove the other flag. Adding xiyuan to confirm.

[xiyuan, 2014/03/14 17:00:54]

The last I talked to Alex, my impression is that we would use it for the new
launcher 2.0 UI (assuming that is what experimental launcher is about). So it is
actual the right thing to change/reuse the start page content. One thing we need
to be careful is the voice recognition code, as it is also hosted in the start
page contents and is actually being used and released.

+                                                          : NULL;
 }
 
 content::WebContents* StartPageService::GetSpeechRecognitionContents() {
   return app_list::switches::IsVoiceSearchEnabled() ? contents_.get() : NULL;
 }
 
 void StartPageService::OnSpeechResult(
     const base::string16& query, bool is_final) {
   if (is_final) {
     speech_result_obtained_ = true;
@@ skipping 29 matching lines @@
   FOR_EACH_OBSERVER(StartPageObserver,
                     observers_,
                     OnSpeechRecognitionStateChanged(new_state));
 }
 
 void StartPageService::Shutdown() {
   contents_.reset();
 }
 
 }  // namespace app_list