[Mac]Implement ViewID support.

chrome/browser/cocoa/tab_controller_target.h

Index: chrome/browser/cocoa/tab_controller_target.h
diff --git a/chrome/browser/cocoa/tab_controller_target.h b/chrome/browser/cocoa/tab_controller_target.h
index df1dad74a8714c3fae2892ce8681e98d80fd2b5f..aa41a08c9cb0f43d61a530bb9f889b05dfe709ce 100644
--- a/chrome/browser/cocoa/tab_controller_target.h
+++ b/chrome/browser/cocoa/tab_controller_target.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2010 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.
 
@@ -21,6 +21,11 @@
 // controller.
 - (BOOL)isCommandEnabled:(TabStripModel::ContextMenuCommand)command
            forController:(TabController*)controller;
+// Returns the index of the tab controller. Returns -1 if not present.
+// Total number of tab controllers owned by the target will be returned
+// in |*total|;
+- (NSInteger)indexForTabController:(TabController*)controller
+                           inTotal:(NSInteger*)total;
 @end
 
 #endif  // CHROME_BROWSER_COCOA_TAB_CONTROLLER_TARGET_H_