WindowAnimationWorklet: gracefully handle detached use

third_party/WebKit/Source/modules/compositorworker/WindowAnimationWorklet.cpp

Index: third_party/WebKit/Source/modules/compositorworker/WindowAnimationWorklet.cpp
diff --git a/third_party/WebKit/Source/modules/compositorworker/WindowAnimationWorklet.cpp b/third_party/WebKit/Source/modules/compositorworker/WindowAnimationWorklet.cpp
index 15a4803470a2130d95c6714f60942b265463d471..dcd582d3453adadcfbc32bfb1f1e569c18e8a4d0 100644
--- a/third_party/WebKit/Source/modules/compositorworker/WindowAnimationWorklet.cpp
+++ b/third_party/WebKit/Source/modules/compositorworker/WindowAnimationWorklet.cpp
@@ -31,6 +31,8 @@ WindowAnimationWorklet& WindowAnimationWorklet::from(LocalDOMWindow& window) {
 
 // static
 Worklet* WindowAnimationWorklet::animationWorklet(DOMWindow& window) {
+  if (!window.frame())
+    return nullptr;
   return from(toLocalDOMWindow(window))
       .animationWorklet(toLocalDOMWindow(window));
 }