Don't show "Save password" prompt for a failed login

components/autofill/content/common/autofill_messages.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Multiply-included message file, hence no include guard.
 
 #include <string>
 #include <vector>
 
 #include "base/strings/string16.h"
@@ skipping 177 matching lines @@
 IPC_MESSAGE_ROUTED2(AutofillHostMsg_FormsSeen,
                     std::vector<autofill::FormData> /* forms */,
                     base::TimeTicks /* timestamp */)
 
 // Notification that password forms have been seen that are candidates for
 // filling/submitting by the password manager.
 IPC_MESSAGE_ROUTED1(AutofillHostMsg_PasswordFormsParsed,
                     std::vector<autofill::PasswordForm> /* forms */)
 
 // Notification that initial layout has occurred and the following password
-// forms are visible on the page (e.g. not set to display:none.)
-IPC_MESSAGE_ROUTED1(AutofillHostMsg_PasswordFormsRendered,
-                    std::vector<autofill::PasswordForm> /* forms */)
+// forms are visible on the page (e.g. not set to display:none.), and whether
+// all frames in the page have been rendered.
+IPC_MESSAGE_ROUTED2(AutofillHostMsg_PasswordFormsRendered,
+                    std::vector<autofill::PasswordForm> /* forms */,
+                    bool /* did_stop_loading */)
 
 // A ping to the browser that PasswordAutofillAgent was constructed. As a
 // consequence, the browser sends AutofillMsg_SetLoggingState with the current
 // state of the logging activity.
 IPC_MESSAGE_ROUTED0(AutofillHostMsg_PasswordAutofillAgentConstructed);
 
 // Notification that this password form was submitted by the user.
 IPC_MESSAGE_ROUTED1(AutofillHostMsg_PasswordFormSubmitted,
                     autofill::PasswordForm /* form */)
 
@@ skipping 76 matching lines @@
 IPC_MESSAGE_ROUTED4(AutofillHostMsg_ShowPasswordSuggestions,
                     autofill::FormFieldData /* the form field */,
                     gfx::RectF /* input field bounds, window-relative */,
                     std::vector<base::string16> /* suggestions */,
                     std::vector<base::string16> /* realms */)
 
 // Inform browser of data list values for the curent field.
 IPC_MESSAGE_ROUTED2(AutofillHostMsg_SetDataList,
                     std::vector<base::string16> /* values */,
                     std::vector<base::string16> /* labels */)