cocoa: add some tab-manipulation menu items

chrome/browser/ui/tabs/tab_strip_model.h

Index: chrome/browser/ui/tabs/tab_strip_model.h
diff --git a/chrome/browser/ui/tabs/tab_strip_model.h b/chrome/browser/ui/tabs/tab_strip_model.h
index 703850fa09c40f17c2a67097832ee230c11fd887..0d47e0efd8849df6ced3525694e0abd9a64c1c34 100644
--- a/chrome/browser/ui/tabs/tab_strip_model.h
+++ b/chrome/browser/ui/tabs/tab_strip_model.h
@@ -411,6 +411,10 @@ class TabStripModel {
   std::vector<int> GetIndicesClosedByCommand(int index,
                                              ContextMenuCommand id) const;
 
+  // Returns true if 'CommandToggleTabAudioMuted' will mute. |index| is the
+  // index supplied to |ExecuteContextMenuCommand|.
+  bool WillContextMenuMute(int index);
+
   // Returns true if 'CommandTogglePinned' will pin. |index| is the index
   // supplied to |ExecuteContextMenuCommand|.
   bool WillContextMenuPin(int index);