app_list::StartPageService: Document and check nulls.

chrome/browser/ui/webui/app_list/start_page_handler.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/webui/app_list/start_page_handler.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 109 matching lines @@
   const extensions::Extension* hotword_extension =
       registry->GetExtensionById(extension_misc::kHotwordExtensionId,
                                  extensions::ExtensionRegistry::ENABLED);
   if (hotword_extension &&
       hotword_extension->version()->CompareTo(
           base::Version(kOldHotwordExtensionVersionString)) <= 0 &&
       !HotwordService::IsExperimentalHotwordingEnabled()) {
     StartPageService* service = StartPageService::Get(profile);
     web_ui()->CallJavascriptFunction(
         "appList.startPage.setHotwordEnabled",
-        base::FundamentalValue(service->HotwordEnabled()));
+        base::FundamentalValue(service && service->HotwordEnabled()));
   }
 }
 #endif
 
 void StartPageHandler::HandleAppListShown(const base::ListValue* args) {
   bool doodle_shown = false;
   if (args->GetBoolean(0, &doodle_shown) && doodle_shown) {
     UMA_HISTOGRAM_ENUMERATION(kAppListDoodleActionHistogram, DOODLE_SHOWN,
                               DOODLE_ACTION_LAST);
   }
@@ skipping 113 matching lines @@
   else if (state_string == "NETWORK_ERROR")
     new_state = SPEECH_RECOGNITION_NETWORK_ERROR;
 
   StartPageService* service =
       StartPageService::Get(Profile::FromWebUI(web_ui()));
   if (service)
     service->OnSpeechRecognitionStateChanged(new_state);
 }
 
 }  // namespace app_list