Delete some unused code found by -Wunused-function

chrome/browser/ui/cocoa/extensions/extension_action_context_menu.mm

 // 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.
 
 #import "chrome/browser/ui/cocoa/extensions/extension_action_context_menu.h"
 
 #include "base/sys_string_conversions.h"
 #include "chrome/browser/api/prefs/pref_change_registrar.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/extension_tab_util.h"
@@ skipping 78 matching lines @@
 // NOTE: You MUST keep this in sync with the |menuItems| NSArray below.
 enum {
   kExtensionContextName = 0,
   kExtensionContextOptions = 2,
   kExtensionContextDisable = 3,
   kExtensionContextUninstall = 4,
   kExtensionContextHide = 5,
   kExtensionContextManage = 7,
 };
 
-int CurrentTabId() {
-  Browser* browser = browser::GetLastActiveBrowser();
-  if(!browser)
-    return -1;
-  WebContents* contents = chrome::GetActiveWebContents(browser);
-  if (!contents)
-    return -1;
-  return ExtensionTabUtil::GetTabId(contents);
-}
-
 }  // namespace
 
 - (id)initWithExtension:(const Extension*)extension
                 browser:(Browser*)browser
         extensionAction:(ExtensionAction*)action{
   if ((self = [super initWithTitle:@""])) {
     action_ = action;
     extension_ = extension;
     browser_ = browser;
 
@@ skipping 86 matching lines @@
 
 - (BOOL)validateMenuItem:(NSMenuItem*)menuItem {
   if ([menuItem tag] == kExtensionContextOptions) {
     // Disable 'Options' if there are no options to set.
     return extension_->options_url().spec().length() > 0;
   }
   return YES;
 }
 
 @end