Add a NavigationThrottle to the public content/ interface

content/browser/loader/navigation_url_loader_impl.h

Index: content/browser/loader/navigation_url_loader_impl.h
diff --git a/content/browser/loader/navigation_url_loader_impl.h b/content/browser/loader/navigation_url_loader_impl.h
index f91458e9f2405e156438842dcb6b99b77848abb5..47e280eab9c7ceafe193506e71cfdbedf44f1710 100644
--- a/content/browser/loader/navigation_url_loader_impl.h
+++ b/content/browser/loader/navigation_url_loader_impl.h
@@ -40,7 +40,8 @@ class NavigationURLLoaderImpl : public NavigationURLLoader {
 
   // Notifies the delegate of a redirect.
   void NotifyRequestRedirected(const net::RedirectInfo& redirect_info,
-                               const scoped_refptr<ResourceResponse>& response);
+                               const scoped_refptr<ResourceResponse>& response,
+                               bool is_external_protocol);
 
   // Notifies the delegate that the response has started.
   void NotifyResponseStarted(const scoped_refptr<ResourceResponse>& response,