Use AuthCredentials throughout the network stack instead of username/password.

net/url_request/url_request_http_job.h

Index: net/url_request/url_request_http_job.h
diff --git a/net/url_request/url_request_http_job.h b/net/url_request/url_request_http_job.h
index d8e8e19459cf5f9c77bd195b1b7ea1665f673217..bc062eadb2b419e2b9b6aab58a3b2d65950732f2 100644
--- a/net/url_request/url_request_http_job.h
+++ b/net/url_request/url_request_http_job.h
@@ -62,8 +62,7 @@ class URLRequestHttpJob : public URLRequestJob {
   void OnReadCompleted(int result);
   void NotifyBeforeSendHeadersCallback(int result);
 
-  void RestartTransactionWithAuth(const string16& username,
-                                  const string16& password);
+  void RestartTransactionWithAuth(const AuthCredentials& credentials);
 
   // Overridden from URLRequestJob:
   virtual void SetUpload(UploadData* upload) OVERRIDE;
@@ -82,8 +81,7 @@ class URLRequestHttpJob : public URLRequestJob {
   virtual bool IsSafeRedirect(const GURL& location) OVERRIDE;
   virtual bool NeedsAuth() OVERRIDE;
   virtual void GetAuthChallengeInfo(scoped_refptr<AuthChallengeInfo>*) OVERRIDE;
-  virtual void SetAuth(const string16& username,
-                       const string16& password) OVERRIDE;
+  virtual void SetAuth(const AuthCredentials& credentials) OVERRIDE;
   virtual void CancelAuth() OVERRIDE;
   virtual void ContinueWithCertificate(X509Certificate* client_cert) OVERRIDE;
   virtual void ContinueDespiteLastError() OVERRIDE;
@@ -107,9 +105,7 @@ class URLRequestHttpJob : public URLRequestJob {
   // Auth states for proxy and origin server.
   AuthState proxy_auth_state_;
   AuthState server_auth_state_;
-
-  string16 username_;
-  string16 password_;
+  AuthCredentials auth_credentials_;
 
   OldCompletionCallbackImpl<URLRequestHttpJob> start_callback_;
   OldCompletionCallbackImpl<URLRequestHttpJob> read_callback_;