Drop document.createEvent support for things still behind a flag

third_party/WebKit/Source/core/events/InputEvent.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 InputEvent_h
 #define InputEvent_h
 
 #include "core/dom/StaticRange.h"
 #include "core/events/InputEventInit.h"
 #include "core/events/UIEvent.h"
 
 namespace blink {
 
 class InputEvent final : public UIEvent {
     DEFINE_WRAPPERTYPEINFO();
 
 public:
-    static InputEvent* create()
-    {
-        return new InputEvent;
-    }
-
     static InputEvent* create(const AtomicString& type, const InputEventInit& initializer)
     {
         return new InputEvent(type, initializer);
     }
 
     enum class InputType {
         None,
         // Insertion.
         InsertText,
         InsertNonText,
@@ skipping 70 matching lines @@
     StaticRangeVector getRanges() const;
 
     bool isInputEvent() const override;
 
     EventDispatchMediator* createMediator() override;
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     friend class InputEventDispatchMediator;
-    InputEvent();
     InputEvent(const AtomicString&, const InputEventInit&);
 
     InputType m_inputType;
     String m_data;
     bool m_isComposing;
     // We have to stored |Range| internally and only expose |StaticRange|, please
     // see comments in |InputEventDispatchMediator::dispatchEvent()|.
     RangeVector m_ranges;
 };
 
 class InputEventDispatchMediator final : public EventDispatchMediator {
 public:
     static InputEventDispatchMediator* create(InputEvent*);
 
 private:
     explicit InputEventDispatchMediator(InputEvent*);
     InputEvent& event() const;
     DispatchEventResult dispatchEvent(EventDispatcher&) const override;
 };
 
 DEFINE_EVENT_TYPE_CASTS(InputEvent);
 
 } // namespace blink
 
 #endif // InputEvent_h