Add password form search using blink::WebNode reference comparison.

components/autofill/content/renderer/form_autofill_util.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/form_autofill_util.h"
 
 #include <map>
 #include <memory>
 #include <set>
 #include <vector>
@@ skipping 1185 matching lines @@
 bool ExtractFormData(const WebFormElement& form_element, FormData* data) {
   return WebFormElementToFormData(
       form_element, WebFormControlElement(), nullptr,
       static_cast<form_util::ExtractMask>(form_util::EXTRACT_VALUE |
                                           form_util::EXTRACT_OPTION_TEXT |
                                           form_util::EXTRACT_OPTIONS),
       data, NULL);
 }
 
 bool IsFormVisible(blink::WebFrame* frame,
+                   const blink::WebFormElement& form_element,
                    const GURL& canonical_action,
                    const GURL& canonical_origin,
                    const FormData& form_data) {
   const GURL frame_origin = GetCanonicalOriginForDocument(frame->document());
   blink::WebVector<WebFormElement> forms;
   frame->document().forms(forms);
 
   // Omitting the action attribute would result in |canonical_origin| for
   // hierarchical schemes like http:, and in an empty URL for non-hierarchical
   // schemes like about: or data: etc.
   const bool action_is_empty = canonical_action.is_empty()
                                || canonical_action == canonical_origin;
 
   // Since empty or unspecified action fields are automatically set to page URL,
   // action field for forms cannot be used for comparing (all forms with
   // empty/unspecified actions have the same value). If an action field is set
   // to the page URL, this method checks ALL fields of the form instead (using
   // FormData.SameFormAs). This is also true if the action was set to the page
   // URL on purpose.
   for (const WebFormElement& form : forms) {
     if (!AreFormContentsVisible(form))
       continue;
 
     GURL iter_canonical_action = GetCanonicalActionForForm(form);
     bool form_action_is_empty = iter_canonical_action.is_empty() ||
                                 iter_canonical_action == frame_origin;
     if (action_is_empty != form_action_is_empty)
       continue;
 
+    // Try to match the WebFormElement reference first.

[dvadym, 2017/03/14 17:11:10]

I think it's better to move up these lines before checking whether action is
empty or not. In such way we can be robust against JavaScript add/remove action

[sense (YandexTeam), 2017/03/15 04:51:24]

Yes, I agree.

+    if (!form_element.isNull() && form.equals(form_element)) {

[dvadym, 2017/03/14 17:11:10]

Nit: you can use == operator (form == form_element). That's used more frequent
then equal.

+      return true;  // Form still exists.
+    }
+
     if (action_is_empty) {  // Both actions are empty, compare all fields.
       FormData extracted_form_data;
       WebFormElementToFormData(form, WebFormControlElement(), nullptr,
                                EXTRACT_NONE, &extracted_form_data, nullptr);
       if (form_data.SameFormAs(extracted_form_data)) {
         return true;  // Form still exists.
       }
     } else {  // Both actions are non-empty, compare actions only.
       if (canonical_action == iter_canonical_action) {
         return true;  // Form still exists.
@@ skipping 565 matching lines @@
     // Zero selection start is for password manager, which can show usernames
     // that do not begin with the user input value.
     selection_start = (offset == base::string16::npos) ? 0 : offset;
   }
 
   input_element->setSelectionRange(selection_start, suggestion.length());
 }
 
 }  // namespace form_util
 }  // namespace autofill