Add a method to tab_utils.h to find out whether a tab is playing audio.

chrome/browser/ui/tabs/tab_utils.cc

Index: chrome/browser/ui/tabs/tab_utils.cc
diff --git a/chrome/browser/ui/tabs/tab_utils.cc b/chrome/browser/ui/tabs/tab_utils.cc
index 93609fe822f8ef7a55997f481f0bb04c00e7072b..d102b7d746fa3274517191bec790321036055eb1 100644
--- a/chrome/browser/ui/tabs/tab_utils.cc
+++ b/chrome/browser/ui/tabs/tab_utils.cc
@@ -4,6 +4,7 @@
 
 #include "chrome/browser/ui/tabs/tab_utils.h"
 
+#include "chrome/browser/media/audio_stream_indicator.h"
 #include "chrome/browser/media/media_internals.h"
 #include "chrome/browser/media/media_stream_capture_indicator.h"
 #include "content/public/browser/render_process_host.h"
@@ -35,4 +36,10 @@ bool ShouldShowRecordingIndicator(content::WebContents* contents) {
                                                   render_view_id);
 }
 
+bool ShouldShowAudioIndicator(content::WebContents* contents) {
+  AudioStreamIndicator* audio_indicator =
+      MediaInternals::GetInstance()->GetAudioStreamIndicator();
+  return audio_indicator->IsPlayingAudio(contents);
+}
+
 }  // namespace chrome