webRequest.onAuthRequired listeners can provide authentication credentials.

chrome/browser/net/chrome_network_delegate.h

Index: chrome/browser/net/chrome_network_delegate.h
diff --git a/chrome/browser/net/chrome_network_delegate.h b/chrome/browser/net/chrome_network_delegate.h
index f36df174edaaceb0ccc8642dc389556310be7485..3f10bf991270e25c6d93143a68a14c847c61da30 100644
--- a/chrome/browser/net/chrome_network_delegate.h
+++ b/chrome/browser/net/chrome_network_delegate.h
@@ -63,8 +63,10 @@ class ChromeNetworkDelegate : public net::NetworkDelegate {
   virtual void OnURLRequestDestroyed(net::URLRequest* request) OVERRIDE;
   virtual void OnPACScriptError(int line_number,
                                 const string16& error) OVERRIDE;
-  virtual void OnAuthRequired(net::URLRequest* request,
-                              const net::AuthChallengeInfo& auth_info) OVERRIDE;
+  virtual int OnAuthRequired(net::URLRequest* request,
+                             const net::AuthChallengeInfo& auth_info,
+                             net::CompletionCallback* callback,
+                             net::AuthCredentials* credentials) OVERRIDE;
 
   scoped_refptr<ExtensionEventRouterForwarder> event_router_;
   void* profile_;