Add the c++ code part of bindings2/

sky/engine/bindings2/dart_event_listener.h

Index: sky/engine/bindings2/dart_event_listener.h
diff --git a/sky/engine/bindings2/dart_event_listener.h b/sky/engine/bindings2/dart_event_listener.h
new file mode 100644
index 0000000000000000000000000000000000000000..2b3d6fdf867102d9889a4cf287cc9f7de4fa8f1c
--- /dev/null
+++ b/sky/engine/bindings2/dart_event_listener.h
@@ -0,0 +1,64 @@
+// 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_BINDINGS2_DART_EVENT_LISTENER_H_
+#define SKY_ENGINE_BINDINGS2_DART_EVENT_LISTENER_H_
+
+#include "dart/runtime/include/dart_api.h"
+#include "sky/engine/core/events/EventListener.h"
+#include "sky/engine/wtf/PassRefPtr.h"
+#include "sky/engine/tonic/dart_converter.h"
+
+namespace blink {
+
+class DartEventListener : public EventListener {
+ public:
+  static PassRefPtr<DartEventListener> FromDart(Dart_Handle handle);
+
+  ~DartEventListener() override;
+
+  bool operator==(const EventListener& other) override {
+    return this == &other;
+  }
+  void handleEvent(ExecutionContext*, Event*) override;
+
+  void AcceptDartGCVisitor(DartGCVisitor& visitor) const override;
+
+ private:
+  explicit DartEventListener(Dart_Handle handle);
+
+  static void Finalize(void* isolate_callback_data,
+                       Dart_WeakPersistentHandle handle,
+                       void* peer);
+
+  base::WeakPtr<DartState> data_state_;
+  Dart_WeakPersistentHandle closure_;
+};
+
+template <>
+struct DartConverter<EventListener*> {
+  static PassRefPtr<EventListener> FromDart(Dart_Handle handle) {
+    return DartEventListener::FromDart(handle);
+  }
+
+  static PassRefPtr<EventListener> FromArguments(Dart_NativeArguments args,
+                                                 int index,
+                                                 Dart_Handle& exception) {
+    return FromDart(Dart_GetNativeArgument(args, index));
+  }
+
+  static PassRefPtr<EventListener> FromArgumentsWithNullCheck(
+      Dart_NativeArguments args,
+      int index,
+      Dart_Handle& exception) {
+    Dart_Handle handle = Dart_GetNativeArgument(args, index);
+    if (Dart_IsNull(handle))
+      return nullptr;
+    return FromDart(handle);
+  }
+};
+
+}  // namespace blink
+
+#endif  // SKY_ENGINE_BINDINGS2_DART_EVENT_LISTENER_H_