[animation-worklet] Implement registerAnimator in worklet scope

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) {}
+
+Animator::~Animator() {}
+
+DEFINE_TRACE(Animator) {
+  visitor->Trace(definition_);
+}
+
+}  // namespace blink