Remove unused DidOpenURL api from WebContentObserver.

content/public/browser/web_contents_observer.h

 // Copyright (c) 2012 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 CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_OBSERVER_H_
 #define CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_OBSERVER_H_
 
 #include "base/process_util.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/navigation_controller.h"
@@ skipping 77 matching lines @@
                            int error_code,
                            const string16& error_description,
                            RenderViewHost* render_view_host) {}
   virtual void DidStartLoading(RenderViewHost* render_view_host) {}
   virtual void DidStopLoading(RenderViewHost* render_view_host) {}
 
   virtual void DidGetUserGesture() {}
   virtual void DidGetIgnoredUIEvent() {}
   virtual void StopNavigation() {}
 
-  virtual void DidOpenURL(const GURL& url,
-                          const Referrer& referrer,
-                          WindowOpenDisposition disposition,
-                          PageTransition transition) {}
-
   virtual void DidOpenRequestedURL(WebContents* new_contents,
                                    const GURL& url,
                                    const Referrer& referrer,
                                    WindowOpenDisposition disposition,
                                    PageTransition transition,
                                    int64 source_frame_id) {}
 
   virtual void WasShown() {}
 
   virtual void AppCacheAccessed(const GURL& manifest_url,
@@ skipping 66 matching lines @@
   void WebContentsImplDestroyed();
 
   WebContentsImpl* web_contents_;
 
   DISALLOW_COPY_AND_ASSIGN(WebContentsObserver);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_OBSERVER_H_