Updates the mic icon status based on the device's audio state.

chrome/browser/ui/app_list/start_page_service.h

Index: chrome/browser/ui/app_list/start_page_service.h
diff --git a/chrome/browser/ui/app_list/start_page_service.h b/chrome/browser/ui/app_list/start_page_service.h
index 61e226055de48df5c1ac945ab210ba55c6aaf6d9..a7b112a2fb744ec03960aad70035426137f140a7 100644
--- a/chrome/browser/ui/app_list/start_page_service.h
+++ b/chrome/browser/ui/app_list/start_page_service.h
@@ -20,6 +20,10 @@
 #include "content/public/browser/web_contents.h"
 #include "ui/app_list/speech_ui_model_observer.h"
 
+#if defined(OS_CHROMEOS)
+#include "chromeos/audio/cras_audio_handler.h"

[tapted, 2014/11/26 02:05:59]

move this to cc file?

[Jun Mukai, 2014/11/26 23:29:51]

Done.

+#endif
+
 namespace extensions {
 class Extension;
 }
@@ -88,6 +92,12 @@ class StartPageService : public KeyedService,
   // getUserMedia() request from the web contents.
   class StartPageWebContentsDelegate;
 
+#if defined(OS_CHROMEOS)
+  // This class observes the change of audio input device availability and
+  // checks if currently the system has valid audio input.
+  class AudioStatus;
+#endif
+
   void LoadContents();
   void UnloadContents();
 
@@ -109,6 +119,10 @@ class StartPageService : public KeyedService,
 
   scoped_ptr<SpeechRecognizer> speech_recognizer_;
 
+#if defined(OS_CHROMEOS)
+  scoped_ptr<AudioStatus> audio_status_;
+#endif
+
   base::WeakPtrFactory<StartPageService> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(StartPageService);