Add supports that allow Autofill to be initiated from textarea field

components/autofill/content/renderer/form_cache.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_cache.h"
 
 #include "base/logging.h"
 #include "base/strings/utf_string_conversions.h"
 #include "components/autofill/content/renderer/form_autofill_util.h"
 #include "components/autofill/core/common/autofill_constants.h"
@@ skipping 161 matching lines @@
   for (std::vector<WebDocument>::const_iterator it =
            documents_to_delete.begin();
        it != documents_to_delete.end(); ++it) {
     web_documents_.erase(*it);
   }
 
   RemoveOldElements(frame, &initial_select_values_);
   RemoveOldElements(frame, &initial_checked_state_);
 }
 
-bool FormCache::ClearFormWithElement(const WebInputElement& element) {
+bool FormCache::ClearFormWithElement(const WebFormControlElement& element) {
   WebFormElement form_element = element.form();
   if (form_element.isNull())
     return false;
 
   std::vector<WebFormControlElement> control_elements;
   ExtractAutofillableElements(form_element, autofill::REQUIRE_NONE,
                               &control_elements);
   for (size_t i = 0; i < control_elements.size(); ++i) {
     WebFormControlElement control_element = control_elements[i];
     // Don't modify the value of disabled fields.
@@ skipping 106 matching lines @@
       element->setAttribute("placeholder",
                             WebString(base::UTF8ToUTF16(placeholder)));
     }
     element->setAttribute("title", WebString(title));
   }
 
   return true;
 }
 
 }  // namespace autofill