Clean up error handling logic for extension tab muting

chrome/browser/extensions/api/tabs/tabs_constants.cc

 // 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.
 
 #include "chrome/browser/extensions/api/tabs/tabs_constants.h"
 
 namespace extensions {
 namespace tabs_constants {
 
 const char kActiveKey[] = "active";
@@ skipping 81 matching lines @@
 const char kIncognitoModeIsForced[] = "Incognito mode is forced. "
     "Cannot open normal windows.";
 const char kURLsNotAllowedInIncognitoError[] = "Cannot open URL \"*\" "
     "in an incognito window.";
 const char kInvalidUrlError[] = "Invalid url: \"*\".";
 const char kNotImplementedError[] = "This call is not yet implemented";
 const char kSupportedInWindowsOnlyError[] = "Supported in Windows only";
 const char kInvalidWindowTypeError[] = "Invalid value for type";
 const char kInvalidWindowStateError[] = "Invalid value for state";
 const char kScreenshotsDisabled[] = "Taking screenshots has been disabled";
-
+const char kCannotUpdateMuteDisabled[] =
+    "Failed to update mute state for tab *, --* must be enabled";
+const char kCannotUpdateMuteCaptured[] =
+    "Cannot update mute state for tab *, tab has audio or video currently "
+    "being captured";
 const char kCannotDetermineLanguageOfUnloadedTab[] =
     "Cannot determine language: tab not loaded";
 
 }  // namespace tabs_constants
 }  // namespace extensions