New interface and function for form association

third_party/WebKit/Source/core/html/FormAssociated.h

+// Copyright 2016 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.
+
+#ifndef FormAssociated_h
+#define FormAssociated_h
+
+namespace blink {
+
+class HTMLFormElement;
+
+// Contains code to associate form with a form associated element
+// https://html.spec.whatwg.org/multipage/forms.html#form-associated-element
+class FormAssociated {
+ public:
+  // HTMLFormElement can be null
+  virtual void associateWith(HTMLFormElement*) = 0;
+};
+
+}  // namespace blink
+
+#endif  // FormAssociated_h