Use wrapper tracing for worklets.

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

Index: third_party/WebKit/Source/modules/compositorworker/Animator.cpp
diff --git a/third_party/WebKit/Source/modules/compositorworker/Animator.cpp b/third_party/WebKit/Source/modules/compositorworker/Animator.cpp
index ee7bfeb0b95c7640d9a496c8a12865589a4da55b..2c7908db7f42990c94a1990f7a53d3ba3bc0e48c 100644
--- a/third_party/WebKit/Source/modules/compositorworker/Animator.cpp
+++ b/third_party/WebKit/Source/modules/compositorworker/Animator.cpp
@@ -12,7 +12,7 @@ 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() {}
 
@@ -20,4 +20,9 @@ DEFINE_TRACE(Animator) {
   visitor->Trace(definition_);
 }
 
+DEFINE_TRACE_WRAPPERS(Animator) {
+  visitor->TraceWrappers(definition_);
+  visitor->TraceWrappers(instance_.Cast<v8::Value>());
+}
+
 }  // namespace blink