Clean up error handling logic for extension tab muting

chrome/browser/ui/tabs/tab_utils.h

 // Copyright (c) 2012 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.
 
 #ifndef CHROME_BROWSER_UI_TABS_TAB_UTILS_H_
 #define CHROME_BROWSER_UI_TABS_TAB_UTILS_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 15 matching lines @@
 // Media state for a tab.  In reality, more than one of these may apply.  See
 // comments for GetTabMediaStateForContents() below.
 enum TabMediaState {
   TAB_MEDIA_STATE_NONE,
   TAB_MEDIA_STATE_RECORDING,  // Audio/Video being recorded, consumed by tab.
   TAB_MEDIA_STATE_CAPTURING,  // Tab contents being captured.
   TAB_MEDIA_STATE_AUDIO_PLAYING,  // Audible audio is playing from the tab.
   TAB_MEDIA_STATE_AUDIO_MUTING,  // Tab audio is being muted.
 };
 
+enum TabMutedResult {
+  TAB_MUTED_RESULT_SUCCESS,
+  TAB_MUTED_RESULT_FAIL_NOT_ENABLED,
+  TAB_MUTED_RESULT_FAIL_TABCAPTURE,
+};
+
 namespace chrome {
 
 // String to indicate reason for muted state change (user, capture, extension
 // id, or empty string)
 extern const char kMutedToggleCauseUser[];
 extern const char kMutedToggleCauseCapture[];
 
 // 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.
@@ skipping 56 matching lines @@
 
 // Returns true if audio mute can be activated/deactivated for the given
 // |contents|.
 bool CanToggleAudioMute(content::WebContents* contents);
 
 // Indicates whether all audio output from |contents| is muted.
 bool IsTabAudioMuted(content::WebContents* contents);
 
 // Sets whether all audio output from |contents| is muted.
 // Cause is extensionid, kMutedToggleCause constant, or empty string
-void SetTabAudioMuted(content::WebContents* contents,
-                      bool mute,
-                      const std::string& cause);
+TabMutedResult SetTabAudioMuted(content::WebContents* contents,
+                                bool mute,
+                                const std::string& cause);
 
 // Get cause of mute (extensionid, kMutedToggleCause constant, or empty string)
 const std::string& GetTabAudioMutedCause(content::WebContents* contents);
 
 // Returns true if the tabs at the |indices| in |tab_strip| are all muted.
 bool AreAllTabsMuted(const TabStripModel& tab_strip,
                      const std::vector<int>& indices);
 
 }  // namespace chrome
 
 #endif  // CHROME_BROWSER_UI_TABS_TAB_UTILS_H_