Add DartController and friends

sky/engine/core/script/dom_dart_state.h

+// Copyright 2015 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.
+
+#ifndef SKY_ENGINE_CORE_SCRIPT_DOM_DART_STATE_H_
+#define SKY_ENGINE_CORE_SCRIPT_DOM_DART_STATE_H_
+
+#include "dart/runtime/include/dart_api.h"
+#include "sky/engine/tonic/dart_state.h"
+#include "sky/engine/core/dom/Document.h"
+#include "sky/engine/wtf/RefPtr.h"
+
+namespace blink {
+class DartLoader;
+class LocalFrame;
+class LocalDOMWindow;
+
+class DOMDartState : public DartState {
+ public:
+  explicit DOMDartState(Document* document);
+  ~DOMDartState() override;
+
+  static DOMDartState* Current();
+
+  static Document* CurrentDocument();
+  static LocalFrame* CurrentFrame();
+  static LocalDOMWindow* CurrentWindow();
+
+  Document* document() const { return document_.get(); }
+  DartLoader& loader() const { return *loader_; }
+
+ private:
+  RefPtr<Document> document_;
+  OwnPtr<DartLoader> loader_;
+};
+
+}
+
+#endif // SKY_ENGINE_CORE_SCRIPT_DOM_DART_STATE_H_