Make tab audible and muted states and cause available for an extension API

chrome/browser/ui/tabs/tab_utils.h

Index: chrome/browser/ui/tabs/tab_utils.h
diff --git a/chrome/browser/ui/tabs/tab_utils.h b/chrome/browser/ui/tabs/tab_utils.h
index 4480a41609f149cbc48f01466975e4358718eaa5..dcf28035f004ece4c5526af0e32991cb75fc8a5a 100644
--- a/chrome/browser/ui/tabs/tab_utils.h
+++ b/chrome/browser/ui/tabs/tab_utils.h
@@ -33,6 +33,8 @@ enum TabMediaState {
 
 namespace chrome {
 
+const char kUserMuteToggleCause[] = "user";

[miu, 2014/12/09 01:56:24]

You should only declare the constant here:

  const char kUserMuteToggleCause[];

And define it in the tab_utils.cc file:

  const char kUserMuteToggleCause[] = "user";

That'll resolve the concern you had about building the string into every file
that includes tab_utils.h.  ;-)

[sky, 2014/12/09 16:37:45]

Is there a reason this is a string and not an enum? If you need a string at a
later date you can always map the enum to a string internally when needed.

+
 // Logic to determine which components (i.e., close button, favicon, and media
 // indicator) of a tab should be shown, given current state.  |capacity|
 // specifies how many components can be shown, given available tab width.
@@ -99,7 +101,9 @@ bool CanToggleAudioMute(content::WebContents* contents);
 
 // Indicates/Sets whether all audio output from |contents| is muted.
 bool IsTabAudioMuted(content::WebContents* contents);
-void SetTabAudioMuted(content::WebContents* contents, bool mute);
+void SetTabAudioMuted(content::WebContents* contents,
+                      bool muted,
+                      const std::string& cause);
 
 // Returns true if the tabs at the |indices| in |tab_strip| are all muted.
 bool AreAllTabsMuted(const TabStripModel& tab_strip,