Add a NavigationThrottle to the public content/ interface

content/browser/loader/navigation_url_loader_impl_core.h

Index: content/browser/loader/navigation_url_loader_impl_core.h
diff --git a/content/browser/loader/navigation_url_loader_impl_core.h b/content/browser/loader/navigation_url_loader_impl_core.h
index 77f90e31bf31ee4bd50e81e4aa040d6757fdf970..8c6e03baa643df0dfa9e3e914a85153384c57dc1 100644
--- a/content/browser/loader/navigation_url_loader_impl_core.h
+++ b/content/browser/loader/navigation_url_loader_impl_core.h
@@ -52,7 +52,8 @@ class NavigationURLLoaderImplCore {
 
   // Notifies |loader_| on the UI thread that the request was redirected.
   void NotifyRequestRedirected(const net::RedirectInfo& redirect_info,
-                               ResourceResponse* response);
+                               ResourceResponse* response,
+                               bool is_external_protocol);
 
   // Notifies |loader_| on the UI thread that the response started.
   void NotifyResponseStarted(ResourceResponse* response,