Use the new hotword extension in the launcher when it is enabled.

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"
 #include "base/metrics/user_metrics.h"
 #include "base/prefs/pref_service.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/media/media_stream_infobar_delegate.h"
 #include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/search/hotword_service.h"
 #include "chrome/browser/search/hotword_service_factory.h"
 #include "chrome/browser/ui/app_list/recommended_apps.h"
 #include "chrome/browser/ui/app_list/start_page_observer.h"
 #include "chrome/browser/ui/app_list/start_page_service_factory.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/common/url_constants.h"
 #include "content/public/browser/notification_details.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
@@ skipping 70 matching lines @@
   return StartPageServiceFactory::GetForProfile(profile);
 }
 
 StartPageService::StartPageService(Profile* profile)
     : profile_(profile),
       profile_destroy_observer_(new ProfileDestroyObserver(this)),
       recommended_apps_(new RecommendedApps(profile)),
       state_(app_list::SPEECH_RECOGNITION_OFF),
       speech_button_toggled_manually_(false),
       speech_result_obtained_(false) {
+  // If experimental hotwording is enabled, then we're always "ready".
+  // Trasitioning into the "hotword recognizing" state is handled by the hotword

[arv (Not doing code reviews), 2014/08/14 15:48:06]

typo

[Anand Mistry (off Chromium), 2014/08/15 00:14:51]

Done.

+  // extension.
+  if (HotwordService::IsExperimentalHotwordingEnabled())
+    state_ = app_list::SPEECH_RECOGNITION_READY;
+
   if (app_list::switches::IsExperimentalAppListEnabled())
     LoadContents();
 }
 
 StartPageService::~StartPageService() {}
 
 void StartPageService::AddObserver(StartPageObserver* observer) {
   observers_.AddObserver(observer);
 }
 
 void StartPageService::RemoveObserver(StartPageObserver* observer) {
   observers_.RemoveObserver(observer);
 }
 
 void StartPageService::AppListShown() {
   if (!contents_) {
     LoadContents();
   } else {
+    bool hotwordEnabled = HotwordEnabled();

[Jun Mukai, 2014/08/14 22:10:08]

variable names are in style of hotword_enabled

Also, why HotwordEnabled() doesn't use
HotwordService::IsExperimentalHotwordingEnabled() directly?

[Anand Mistry (off Chromium), 2014/08/15 00:14:51]

Done.
Because HotwordEnabled() is used in a number of other places where I don't want
it to take into account IsExperimentalHotwordingEnabled() in this way. Here, I
don't just want to know whether hotwording is enabled or not, but also whether
or not to use the hotwording built into the start page. Two orthogonal concepts.

+    // If experimental hotwording is enabled, don't enable hotwording in the
+    // start page, since the hotword extension is taking care of this.
+    if (HotwordService::IsExperimentalHotwordingEnabled())
+      hotwordEnabled = false;

[Jun Mukai, 2014/08/14 22:10:08]

You can simply
hotword_enabled = HotwordEnabled() &&
!HotwordService::IsExperimentalHotwordingEnabled();

[Anand Mistry (off Chromium), 2014/08/15 00:14:51]

Done.

+
     contents_->GetWebUI()->CallJavascriptFunction(
         "appList.startPage.onAppListShown",
-        base::FundamentalValue(HotwordEnabled()));
+        base::FundamentalValue(hotwordEnabled));
   }
 }
 
 void StartPageService::AppListHidden() {
   contents_->GetWebUI()->CallJavascriptFunction(
       "appList.startPage.onAppListHidden");
   if (!app_list::switches::IsExperimentalAppListEnabled())
     UnloadContents();
 }
 
 void StartPageService::ToggleSpeechRecognition() {
   speech_button_toggled_manually_ = true;
   contents_->GetWebUI()->CallJavascriptFunction(
       "appList.startPage.toggleSpeechRecognition");
 }
 
 bool StartPageService::HotwordEnabled() {
+  if (HotwordService::IsExperimentalHotwordingEnabled())

[arv (Not doing code reviews), 2014/08/14 15:48:06]

needs {}

[Anand Mistry (off Chromium), 2014/08/15 00:14:51]

Done.

+    return HotwordServiceFactory::IsServiceAvailable(profile_) &&
+        profile_->GetPrefs()->GetBoolean(prefs::kHotwordSearchEnabled);
 #if defined(OS_CHROMEOS)
   return HotwordServiceFactory::IsServiceAvailable(profile_) &&
       profile_->GetPrefs()->GetBoolean(prefs::kHotwordSearchEnabled);
 #else
   return false;
 #endif
 }
 
 content::WebContents* StartPageService::GetStartPageContents() {
   return app_list::switches::IsExperimentalAppListEnabled() ? contents_.get()
@@ skipping 69 matching lines @@
       content::Referrer(),
       content::PAGE_TRANSITION_AUTO_TOPLEVEL,
       std::string());
 }
 
 void StartPageService::UnloadContents() {
   contents_.reset();
 }
 
 }  // namespace app_list