WindowAnimationWorklet: gracefully handle detached use

third_party/WebKit/Source/modules/compositorworker/WindowAnimationWorklet.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/compositorworker/WindowAnimationWorklet.h"
 
 #include "core/dom/Document.h"
 #include "core/frame/LocalDOMWindow.h"
 #include "core/frame/LocalFrame.h"
 #include "modules/compositorworker/AnimationWorklet.h"
@@ skipping 13 matching lines @@
       Supplement<LocalDOMWindow>::from(window, supplementName()));
   if (!supplement) {
     supplement = new WindowAnimationWorklet(window);
     provideTo(window, supplementName(), supplement);
   }
   return *supplement;
 }
 
 // static
 Worklet* WindowAnimationWorklet::animationWorklet(DOMWindow& window) {
+  if (!window.frame())
+    return nullptr;
   return from(toLocalDOMWindow(window))
       .animationWorklet(toLocalDOMWindow(window));
 }
 
 AnimationWorklet* WindowAnimationWorklet::animationWorklet(
     LocalDOMWindow& window) {
   if (!m_animationWorklet && getExecutionContext()) {
     DCHECK(window.frame());
     m_animationWorklet = AnimationWorklet::create(window.frame());
   }
@@ skipping 13 matching lines @@
   m_animationWorklet = nullptr;
 }
 
 DEFINE_TRACE(WindowAnimationWorklet) {
   visitor->trace(m_animationWorklet);
   Supplement<LocalDOMWindow>::trace(visitor);
   ContextLifecycleObserver::trace(visitor);
 }
 
 }  // namespace blink