[nacltoons] Cleanup initial game code.

nacltoons/src/physics_layer.h

 // Copyright (c) 2013 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 PHYSICS_LAYER_H_
 #define PHYSICS_LAYER_H_
 
 #include "cocos2d.h"
 #include "Box2D/Box2D.h"
 
 USING_NS_CC;
 
 /**
  * Physics layer that the user interacts with.
  */
 class PhysicsLayer : public CCLayerColor {
  public:
   PhysicsLayer() {}
   ~PhysicsLayer();
+  // add static create() method which encapsulates new + init
   CREATE_FUNC(PhysicsLayer);
   virtual bool init();
   virtual void ccTouchesEnded(CCSet* touches, CCEvent* event);
 
  private:
   void AddNewSpriteAtPosition(CCPoint p);
   void UpdateWorld(float dt);
   bool InitPhysics();
 
   CCTexture2D* sprite_texture_;
   b2World* world_;
 };
 
-#endif // !PHYSICS_LAYER_H_
+#endif  // PHYSICS_LAYER_H_