Use correct element for Form Not Secure warning

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 1601 matching lines @@
     FormFieldData* field) {
   return UnownedFormElementsAndFieldSetsToFormData(
       fieldsets, control_elements, element, document,
       field_value_and_properties_map, extract_mask, form, field);
 }
 
 
 bool FindFormAndFieldForFormControlElement(const WebFormControlElement& element,
                                            FormData* form,
                                            FormFieldData* field) {
+  DCHECK(!element.isNull());
+
   if (!IsAutofillableElement(element))
     return false;
 
   ExtractMask extract_mask =
       static_cast<ExtractMask>(EXTRACT_VALUE | EXTRACT_OPTIONS);
   const WebFormElement form_element = element.form();
   if (form_element.isNull()) {
     // No associated form, try the synthetic form for unowned form elements.
     WebDocument document = element.document();
     std::vector<WebElement> fieldsets;
@@ skipping 172 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