[worklets] Fixes leak document leak for AnimationWorklet.

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 006bbf4825808aea14907a25222bb9dcb95e0847..3512051bf191613a1f4e16497cccfa9af04b78cf 100644
--- a/third_party/WebKit/Source/modules/compositorworker/WindowAnimationWorklet.cpp
+++ b/third_party/WebKit/Source/modules/compositorworker/WindowAnimationWorklet.cpp
@@ -39,6 +39,11 @@ AnimationWorklet* WindowAnimationWorklet::animationWorklet() {
   return m_animationWorklet.get();
 }
 
+void WindowAnimationWorklet::frameDestroyed() {
+  m_animationWorklet.clear();
+  DOMWindowProperty::frameDestroyed();
+}
+
 DEFINE_TRACE(WindowAnimationWorklet) {
   visitor->trace(m_animationWorklet);
   Supplement<LocalDOMWindow>::trace(visitor);