Merge "Remove undefined functions from VirtualTouchpadClient." am: 622d91bf

 public:

  // VirtualTouchpad implementation:

  static std::unique_ptr<VirtualTouchpad> Create();

  status_t Attach() override;

  status_t Detach() override;

  status_t Touch(int touchpad, float x, float y, float pressure) override;

  status_t ButtonState(int touchpad, int buttons) override;

  status_t Scroll(int touchpad, float x, float y) override;

  void dumpInternal(String8& result) override;

 protected:

  VirtualTouchpadClient() {}