Add OVERRIDE to chrome/browser/.

chrome/browser/history/history_tab_helper.h

Index: chrome/browser/history/history_tab_helper.h
diff --git a/chrome/browser/history/history_tab_helper.h b/chrome/browser/history/history_tab_helper.h
index a7b31bca01ed70a8acac385b61c2aba3a6f124d6..b5f83ef09b8101b3923f15d692da9806e55c2e2c 100644
--- a/chrome/browser/history/history_tab_helper.h
+++ b/chrome/browser/history/history_tab_helper.h
@@ -42,18 +42,18 @@ class HistoryTabHelper : public TabContentsObserver,
 
  private:
   // TabContentsObserver implementation.
-  virtual bool OnMessageReceived(const IPC::Message& message);
+  virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
   virtual void DidNavigateMainFrame(
       const content::LoadCommittedDetails& details,
-      const ViewHostMsg_FrameNavigate_Params& params);
+      const ViewHostMsg_FrameNavigate_Params& params) OVERRIDE;
   virtual void DidNavigateAnyFrame(
       const content::LoadCommittedDetails& details,
-      const ViewHostMsg_FrameNavigate_Params& params);
+      const ViewHostMsg_FrameNavigate_Params& params) OVERRIDE;
 
   // content::NotificationObserver implementation.
   virtual void Observe(int type,
                        const content::NotificationSource& source,
-                       const content::NotificationDetails& details);
+                       const content::NotificationDetails& details) OVERRIDE;
 
   void OnPageContents(const GURL& url,
                       int32 page_id,