Suggest to fill password change forms

components/autofill/content/renderer/password_form_conversion_utils.cc

 // 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.
 
 #include "components/autofill/content/renderer/password_form_conversion_utils.h"
 
 #include <vector>
 
 #include "base/lazy_instance.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 125 matching lines @@
 
   if (passwords.empty())
     return false;
 
   switch (passwords.size()) {
     case 1:
       // Single password, easy.
       *current_password = passwords[0];
       break;
     case 2:
-      if (passwords[0].value() == passwords[1].value()) {
-        // Two identical passwords: assume we are seeing a new password with a
-        // confirmation. This can be either a sign-up form or a password change
-        // form that does not ask for the old password.
+      if (!passwords[0].value().isEmpty() &&
+          passwords[0].value() == passwords[1].value()) {
+        // Two identical non-empty passwords: assume we are seeing a new
+        // password with a confirmation. This can be either a sign-up form or a
+        // password change form that does not ask for the old password.
         *new_password = passwords[0];
       } else {
         // Assume first is old password, second is new (no choice but to guess).
+        // This case also includes empty passwords in order to allow filling of
+        // password change forms (that also could autofill for sign up form, but
+        // we can't do anything with this using only client side information).
         *current_password = passwords[0];
         *new_password = passwords[1];
       }
       break;
     default:
       if (!passwords[0].value().isEmpty() &&
           passwords[0].value() == passwords[1].value() &&
           passwords[0].value() == passwords[2].value()) {
         // All three passwords are the same and non-empty? This does not make
         // any sense, give up.
@@ skipping 323 matching lines @@
   WebFormElementToFormData(web_form,
                            blink::WebFormControlElement(),
                            EXTRACT_NONE,
                            &password_form->form_data,
                            NULL /* FormFieldData */);
 
   return password_form.Pass();
 }
 
 }  // namespace autofill