[Mac]Implement ViewID support.

chrome/browser/renderer_host/render_widget_host_view_mac.mm

 // 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.
 
 #include <QuartzCore/QuartzCore.h>
 
 #include "chrome/browser/renderer_host/render_widget_host_view_mac.h"
 
 #include "app/surface/io_surface_support_mac.h"
 #import "base/chrome_application_mac.h"
 #include "base/histogram.h"
 #include "base/logging.h"
 #import "base/scoped_nsobject.h"
 #include "base/string_util.h"
 #include "base/sys_string_conversions.h"
 #include "chrome/browser/browser_trial.h"
 #import "chrome/browser/cocoa/rwhvm_editcommand_helper.h"
+#import "chrome/browser/cocoa/view_id_util.h"
 #include "chrome/browser/plugin_process_host.h"
 #include "chrome/browser/renderer_host/backing_store_mac.h"
 #include "chrome/browser/renderer_host/render_process_host.h"
 #include "chrome/browser/renderer_host/render_view_host.h"
 #include "chrome/browser/renderer_host/render_widget_host.h"
 #include "chrome/browser/spellchecker_platform_engine.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/native_web_keyboard_event.h"
 #include "chrome/common/edit_command.h"
 #include "chrome/common/plugin_messages.h"
@@ skipping 2069 matching lines @@
 - (void)confirmComposition {
   if (!hasMarkedText_)
     return;
 
   if (renderWidgetHostView_->render_widget_host_)
     renderWidgetHostView_->render_widget_host_->ImeConfirmComposition();
 
   [self cancelComposition];
 }
 
+// Tag is used solely for ViewID. Override to prevent changing of it.
+- (NSInteger)tag {
+  return view_id_util::ViewIDToTag(VIEW_ID_TAB_CONTAINER_FOCUS_VIEW);
+}
+
 @end