Remove DOMWindowProperty from WindowPaintWorklet

third_party/WebKit/Source/modules/csspaint/WindowPaintWorklet.cpp

 // 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.
 
 #include "modules/csspaint/WindowPaintWorklet.h"
 
 #include "core/frame/LocalDOMWindow.h"
 #include "core/frame/LocalFrame.h"
 #include "modules/csspaint/PaintWorklet.h"
 
 namespace blink {
 
 WindowPaintWorklet::WindowPaintWorklet(LocalDOMWindow& window)
-    : DOMWindowProperty(window.frame()) {}
+    : Supplement<LocalDOMWindow>(window) {}
 
 const char* WindowPaintWorklet::supplementName() {
   return "WindowPaintWorklet";
 }
 
 // static
 WindowPaintWorklet& WindowPaintWorklet::from(LocalDOMWindow& window) {
   WindowPaintWorklet* supplement = static_cast<WindowPaintWorklet*>(
       Supplement<LocalDOMWindow>::from(window, supplementName()));
   if (!supplement) {
     supplement = new WindowPaintWorklet(window);
     provideTo(window, supplementName(), supplement);
   }
   return *supplement;
 }
 
 // static
 Worklet* WindowPaintWorklet::paintWorklet(DOMWindow& window) {
   return from(toLocalDOMWindow(window)).paintWorklet();
 }
 
 PaintWorklet* WindowPaintWorklet::paintWorklet() {
-  if (!m_paintWorklet && frame())
-    m_paintWorklet = PaintWorklet::create(frame());
+  if (!m_paintWorklet && host() && host()->frame())

[sof, 2017/01/13 07:29:13]

we really have to support operating in a host()-free setting? (if we can
maintain the invariant that host() can never be null for supplements, that'd be
simpler.)

+    m_paintWorklet = PaintWorklet::create(host()->frame());
   return m_paintWorklet.get();
 }
 
 DEFINE_TRACE(WindowPaintWorklet) {
   visitor->trace(m_paintWorklet);
   Supplement<LocalDOMWindow>::trace(visitor);
-  DOMWindowProperty::trace(visitor);
 }
 
 }  // namespace blink