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

content/browser/browser_url_handler_impl.h

Index: content/browser/browser_url_handler_impl.h
diff --git a/content/browser/browser_url_handler_impl.h b/content/browser/browser_url_handler_impl.h
index 240554b76813a2ef7c8aa31eb045f46c2ed0ea0b..4084418abc2aa0f6f13ab2382aae556707ad4b71 100644
--- a/content/browser/browser_url_handler_impl.h
+++ b/content/browser/browser_url_handler_impl.h
@@ -26,9 +26,13 @@ class CONTENT_EXPORT BrowserURLHandlerImpl : public BrowserURLHandler {
   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);
@@ -39,6 +43,9 @@ class CONTENT_EXPORT BrowserURLHandlerImpl : public BrowserURLHandler {
   ~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_;