Add context menus to tabs.

chrome/browser/cocoa/tab_controller.h

Index: chrome/browser/cocoa/tab_controller.h
===================================================================
--- chrome/browser/cocoa/tab_controller.h	(revision 20045)
+++ chrome/browser/cocoa/tab_controller.h	(working copy)
@@ -34,8 +34,9 @@
 
 @interface TabController : NSViewController {
  @private
-  IBOutlet NSButton *backgroundButton_;
+  IBOutlet NSButton* backgroundButton_;
   IBOutlet NSView* iconView_;
+  IBOutlet NSMenu* contextMenu_;
   BOOL selected_;
   TabLoadingState loadingState_;
   id<TabControllerTarget> target_;  // weak, where actions are sent
@@ -59,6 +60,9 @@
 // perform the close.
 - (IBAction)closeTab:(id)sender;
 
+// Dispatches the command in the tag to the registered target object.
+- (IBAction)commandDispatch:(id)sender;
+
 // Replace the current icon view with the given view. |iconView| will be
 // resized to the size of the current icon view.
 - (void)setIconView:(NSView*)iconView;