Add FormDataEvent interface.

It is behind the flag "FormDataEvent". The flag is off by default, and
tests will be added later.

Bug: 825684
Change-Id: If152940a52e684a1c64f75ee2f60fbd18b91954d
Reviewed-on: https://chromium-review.googlesource.com/995114Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
Commit-Queue: Kent Tamura <tkent@chromium.org>
Cr-Commit-Position: refs/heads/master@{#548244}

third_party/WebKit/Source/core/BUILD.gn

@@ -383,6 +383,7 @@ generate_event_interfaces("core_event_interfaces") {
     "events/TransitionEvent.idl",
     "events/UIEvent.idl",
     "events/WheelEvent.idl",
+    "html/forms/FormDataEvent.idl",
     "html/track/TrackEvent.idl",
     "mojo/test/MojoInterfaceRequestEvent.idl",
   ]

third_party/WebKit/Source/core/core_idl_files.gni

@@ -257,6 +257,7 @@ core_idl_files =
                     "html/canvas/TextMetrics.idl",
                     "html/custom/CustomElementRegistry.idl",
                     "html/forms/FormData.idl",
+                    "html/forms/FormDataEvent.idl",
                     "html/forms/HTMLButtonElement.idl",
                     "html/forms/HTMLDataListElement.idl",
                     "html/forms/HTMLFieldSetElement.idl",

third_party/WebKit/Source/core/events/event_type_names.json5

@@ -116,6 +116,7 @@
     "focusin",
     "focusout",
     "foreignfetch",
+    "formdata",
     "freeze",
     "fullscreenchange",
     "fullscreenerror",

third_party/WebKit/Source/core/html/BUILD.gn

@@ -351,6 +351,8 @@ blink_core_sources("html") {
     "forms/FormController.h",
     "forms/FormData.cpp",
     "forms/FormData.h",
+    "forms/FormDataEvent.cpp",
+    "forms/FormDataEvent.h",
     "forms/HTMLButtonElement.cpp",
     "forms/HTMLButtonElement.h",
     "forms/HTMLDataListElement.cpp",

third_party/WebKit/Source/core/html/forms/FormDataEvent.cpp

+// Copyright 2018 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 "core/html/forms/FormDataEvent.h"
+
+#include "core/html/forms/FormData.h"
+
+namespace blink {
+
+FormDataEvent::FormDataEvent(FormData& form_data)
+    : Event(EventTypeNames::formdata, Bubbles::kYes, Cancelable::kNo),
+      form_data_(form_data) {}
+
+FormDataEvent* FormDataEvent::Create(FormData& form_data) {
+  return new FormDataEvent(form_data);
+}
+
+void FormDataEvent::Trace(Visitor* visitor) {
+  visitor->Trace(form_data_);
+  Event::Trace(visitor);
+}
+
+const AtomicString& FormDataEvent::InterfaceName() const {
+  return EventNames::FormDataEvent;
+}
+
+}  // namespace blink

third_party/WebKit/Source/core/html/forms/FormDataEvent.h

+// Copyright 2018 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 FormDataEvent_h
+#define FormDataEvent_h
+
+#include "core/dom/events/Event.h"
+
+namespace blink {
+
+class FormData;
+
+class FormDataEvent : public Event {
+  DEFINE_WRAPPERTYPEINFO();
+
+ public:
+  static FormDataEvent* Create(FormData& form_data);
+  void Trace(Visitor* visitor) override;
+
+  FormData* formData() const { return form_data_; };
+
+  const AtomicString& InterfaceName() const override;
+
+ private:
+  FormDataEvent(FormData& form_data);
+
+  Member<FormData> form_data_;
+};
+
+}  // namespace blink
+
+#endif  // FormDataEvent_h

third_party/WebKit/Source/core/html/forms/FormDataEvent.idl

+// Copyright 2018 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.
+
+// https://docs.google.com/document/d/1JO8puctCSpW-ZYGU8lF-h4FWRIDQNDVexzHoOQ2iQmY/edit?pli=1#heading=h.je8c7y5qpgki
+
+[
+  Exposed=Window,
+  RuntimeEnabled=FormDataEvent
+]
+interface FormDataEvent : Event {
+  readonly attribute FormData formData;
+};

third_party/WebKit/Source/platform/runtime_enabled_features.json5

@@ -491,6 +491,9 @@
     {
       name: "ForceTallerSelectPopup",
     },
+    {
+      name: "FormDataEvent",
+    },
     {
       name: "FractionalMouseEvent",
     },