Add the "virtual" keyword on method overrides that are missing it.

chrome/browser/renderer_host/site_instance.h

 // Copyright (c) 2009 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.
 
 #ifndef CHROME_BROWSER_RENDERER_HOST_SITE_INSTANCE_H_
 #define CHROME_BROWSER_RENDERER_HOST_SITE_INSTANCE_H_
 #pragma once
 
 #include "chrome/browser/renderer_host/render_process_host.h"
 #include "chrome/common/notification_observer.h"
@@ skipping 143 matching lines @@
   // extension as the host. This has the effect of grouping apps together in
   // a common SiteInstance.
   static GURL GetEffectiveURL(Profile* profile, const GURL& url);
 
   // Returns the type of renderer process this instance belongs in, for grouping
   // purposes.
   RenderProcessHost::Type GetRendererType();
 
  private:
   // NotificationObserver implementation.
-  void Observe(NotificationType type,
-               const NotificationSource& source,
-               const NotificationDetails& details);
+  virtual void Observe(NotificationType type,
+                       const NotificationSource& source,
+                       const NotificationDetails& details);
 
   NotificationRegistrar registrar_;
 
   // BrowsingInstance to which this SiteInstance belongs.
   scoped_refptr<BrowsingInstance> browsing_instance_;
 
   // Factory for new RenderProcessHosts, not owned by this class. NULL indiactes
   // that the default BrowserRenderProcessHost should be created.
   const RenderProcessHostFactory* render_process_host_factory_;
 
@@ skipping 11 matching lines @@
   // The web site that this SiteInstance is rendering pages for.
   GURL site_;
 
   // Whether SetSite has been called.
   bool has_site_;
 
   DISALLOW_COPY_AND_ASSIGN(SiteInstance);
 };
 
 #endif  // CHROME_BROWSER_RENDERER_HOST_SITE_INSTANCE_H_