[Mac]Implement ViewID support. (third approach)

chrome/browser/cocoa/reload_button.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.
 
 #import "chrome/browser/cocoa/reload_button.h"
 
 #include "base/nsimage_cache_mac.h"
 #include "chrome/app/chrome_dll_resource.h"
+#import "chrome/browser/cocoa/view_id_util.h"
 
 namespace {
 
 NSString* const kReloadImageName = @"reload_Template.pdf";
 NSString* const kStopImageName = @"stop_Template.pdf";
 
 }  // namespace
 
 @implementation ReloadButton
 
@@ skipping 79 matching lines @@
 
   // Reload mode was requested during the hover.
   if (pendingReloadMode_)
     [self setIsLoading:NO force:YES];
 }
 
 - (BOOL)isMouseInside {
   return trackingArea_ && isMouseInside_;
 }
 
+- (ViewID)viewID {
+  return VIEW_ID_RELOAD_BUTTON;
+}
+
 @end  // ReloadButton
 
 @implementation ReloadButton (Testing)
 
 - (NSTrackingArea*)trackingArea {
   return trackingArea_;
 }
 
 @end