Rename sky/engine/bindings2 to sky/engine/bindings

sky/engine/bindings/dart_callback.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_BINDINGS2_DART_CALLBACK_H_
-#define SKY_ENGINE_BINDINGS2_DART_CALLBACK_H_
+#ifndef SKY_ENGINE_BINDINGS_DART_CALLBACK_H_
+#define SKY_ENGINE_BINDINGS_DART_CALLBACK_H_
 
 #include "dart/runtime/include/dart_api.h"
 #include "sky/engine/tonic/dart_persistent_value.h"
 
 namespace blink {
 
 class DartCallback {
  public:
   DartCallback(DartState* dart_state,
                Dart_Handle callback,
                Dart_Handle& exception);
   ~DartCallback();
 
   bool handleEvent(int argc, Dart_Handle* argv);
 
   bool IsIsolateAlive() const;
   Dart_Isolate GetIsolate() const;
 
  private:
   DartPersistentValue callback_;
 };
 }
 
-#endif  // SKY_ENGINE_BINDINGS2_DART_CALLBACK_H_
+#endif  // SKY_ENGINE_BINDINGS_DART_CALLBACK_H_