[Mac]Implement ViewID support.

chrome/browser/cocoa/bookmark_bar_view.mm

Index: chrome/browser/cocoa/bookmark_bar_view.mm
diff --git a/chrome/browser/cocoa/bookmark_bar_view.mm b/chrome/browser/cocoa/bookmark_bar_view.mm
index f2f2ea5942636b16a53b559cb4626789cc2775bb..ebe5ad074913bfced645f790f7701557eae5dbb9 100644
--- a/chrome/browser/cocoa/bookmark_bar_view.mm
+++ b/chrome/browser/cocoa/bookmark_bar_view.mm
@@ -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.
 
@@ -10,6 +10,7 @@
 #import "chrome/browser/cocoa/bookmark_button.h"
 #import "chrome/browser/cocoa/bookmark_folder_target.h"
 #import "chrome/browser/cocoa/themed_window.h"
+#import "chrome/browser/cocoa/view_id_util.h"
 #import "third_party/mozilla/NSPasteboard+Utils.h"
 
 @interface BookmarkBarView (Private)
@@ -249,4 +250,9 @@
   controller_ = controller;
 }
 
+// Tag is used solely for ViewID. Override to prevent changing of it.
+- (NSInteger)tag {
+  return view_id_util::ViewIDToTag(VIEW_ID_BOOKMARK_BAR);
+}
+
 @end  // @implementation BookmarkBarView