Disable mute/unmute when media does not have an audio track.

webkit/glue/context_menu.h

 // Copyright (c) 2006-2009 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 WEBKIT_GLUE_CONTEXT_MENU_H_
 #define WEBKIT_GLUE_CONTEXT_MENU_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 64 matching lines @@
     PAUSED = 0x2,
     MUTED = 0x4,
     LOOP = 0x8,
     CAN_SAVE = 0x10,
   };
 
   // A bitfield representing the current state of the player, such as
   // playing, muted, etc.
   int32 player_state;
 
+  // Whether a playable audio track is present.
+  bool has_audio;
+
   ContextMenuMediaParams()
-      : player_state(NO_STATE) {
+      : player_state(NO_STATE), has_audio(false) {
   }
 };
 
 // Parameters structure for ViewHostMsg_ContextMenu.
 // FIXME(beng): This would be more useful in the future and more efficient
 //              if the parameters here weren't so literally mapped to what
 //              they contain for the ContextMenu task. It might be better
 //              to make the string fields more generic so that this object
 //              could be used for more contextual actions.
 struct ContextMenuParams {
@@ skipping 51 matching lines @@
   int edit_flags;
 
   // The security info for the resource we are showing the menu on.
   std::string security_info;
 
   // The character encoding of the frame on which the menu is invoked.
   std::string frame_charset;
 };
 
 #endif  // WEBKIT_GLUE_CONTEXT_MENU_H_