Convert PrerenderContents to use the new navigation callbacks.

content/public/browser/navigation_handle.h

 // Copyright 2015 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_NAVIGATION_HANDLE_H_
 #define CONTENT_PUBLIC_BROWSER_NAVIGATION_HANDLE_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 142 matching lines @@
 
   // Whether the navigation happened in the same page. Examples of same page
   // navigations are:
   // * reference fragment navigations
   // * pushState/replaceState
   virtual bool IsSamePage() = 0;
 
   // Whether the navigation has encountered a server redirect or not.
   virtual bool WasServerRedirect() = 0;
 
+  // Lists the redirects that occurred on the way to the current page. The
+  // current page is the last one in the list (so even when there's no redirect,
+  // there will be one entry in the list).
+  virtual const std::vector<GURL>& GetRedirectChain() = 0;
+
   // Whether the navigation has committed. This returns true for either
   // successful commits or error pages that replace the previous page
   // (distinguished by |IsErrorPage|), and false for errors that leave the user
   // on the previous page.
   virtual bool HasCommitted() = 0;
 
   // Whether the navigation resulted in an error page.
   // Note that if an error page reloads, this will return true even though
   // GetNetErrorCode will be net::OK.
   virtual bool IsErrorPage() = 0;
@@ skipping 78 matching lines @@
 
   // The NavigationData that the embedder returned from
   // ResourceDispatcherHostDelegate::GetNavigationData during commit. This will
   // be a clone of the NavigationData.
   virtual NavigationData* GetNavigationData() = 0;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_NAVIGATION_HANDLE_H_