Move URL fixup to a preliminary phase that doesn't affect virtual URLs.

content/browser/browser_url_handler_impl.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_BROWSER_BROWSER_URL_HANDLER_IMPL_H_
 #define CONTENT_BROWSER_BROWSER_URL_HANDLER_IMPL_H_
 
 #include <vector>
 #include <utility>
 
 #include "base/gtest_prod_util.h"
 #include "base/memory/singleton.h"
 #include "content/public/browser/browser_url_handler.h"
 
 class GURL;
 
 namespace content {
 class BrowserContext;
 
 class CONTENT_EXPORT BrowserURLHandlerImpl : public BrowserURLHandler {
  public:
   // Returns the singleton instance.
   static BrowserURLHandlerImpl* GetInstance();
 
   // BrowserURLHandler implementation:
   void RewriteURLIfNecessary(GURL* url,
                              BrowserContext* browser_context,
                              bool* reverse_on_redirect) override;
+  void SetFixupHandler(URLHandler handler) override;
   // Add the specified handler pair to the list of URL handlers.
   void AddHandlerPair(URLHandler handler, URLHandler reverse_handler) override;
 
+  // Fixes up the URL before rewriting occurs.
+  void FixupURLBeforeRewrite(GURL* url, BrowserContext* browser_context);
+
   // Reverses the rewriting that was done for |original| using the new |url|.
   bool ReverseURLRewrite(GURL* url, const GURL& original,
                          BrowserContext* browser_context);
 
  private:
   // This object is a singleton:
   BrowserURLHandlerImpl();
   ~BrowserURLHandlerImpl() override;
   friend struct DefaultSingletonTraits<BrowserURLHandlerImpl>;
 
+  // A URLHandler to run in a preliminary phase, before rewriting is done.
+  URLHandler fixup_handler_;
+
   // The list of known URLHandlers, optionally with reverse-rewriters.
   typedef std::pair<URLHandler, URLHandler> HandlerPair;
   std::vector<HandlerPair> url_handlers_;
 
   FRIEND_TEST_ALL_PREFIXES(BrowserURLHandlerImplTest, BasicRewriteAndReverse);
   FRIEND_TEST_ALL_PREFIXES(BrowserURLHandlerImplTest, NullHandlerReverse);
   FRIEND_TEST_ALL_PREFIXES(BrowserURLHandlerImplTest, ViewSourceReverse);
 
   DISALLOW_COPY_AND_ASSIGN(BrowserURLHandlerImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_BROWSER_URL_HANDLER_IMPL_H_