Use wrapper tracing for worklets.

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

 // Copyright 2017 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/Animator.h"
 
 #include "modules/compositorworker/AnimatorDefinition.h"
 #include "platform/bindings/ScriptState.h"
 
 namespace blink {
 
 Animator::Animator(v8::Isolate* isolate,
                    AnimatorDefinition* definition,
                    v8::Local<v8::Object> instance)
-    : definition_(definition), instance_(isolate, instance) {}
+    : definition_(this, definition), instance_(isolate, this, instance) {}
 
 Animator::~Animator() {}
 
 DEFINE_TRACE(Animator) {
   visitor->Trace(definition_);
 }
 
+DEFINE_TRACE_WRAPPERS(Animator) {
+  visitor->TraceWrappers(definition_);
+  visitor->TraceWrappers(instance_.Cast<v8::Value>());
+}
+
 }  // namespace blink