Clean up input handling in VulkanViewer

tools/vulkan/win/Window_win.h

 /*
 * Copyright 2016 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
 #ifndef Window_win_DEFINED
 #define Window_win_DEFINED
 
 #include <windows.h>
 #include "../Window.h"
 
 class Window_win : public Window {
 public:
     Window_win() : Window() {}
     ~Window_win() override {}
 
     bool init(HINSTANCE instance);
 
     void setTitle(const char*) override;
     void show() override;
 
-    // event callbacks
-    bool onKeyboard(UINT nChar, bool bKeyDown, bool bAltDown);
-    bool onMouse(bool bLeftButtonDown, bool bRightButtonDown, bool bMiddleButtonDown,
-                 bool bSideButton1Down, bool bSideButton2Down, int nMouseWheelDelta,
-                 int xPos, int yPos);
-
     bool attach(BackEndTypes attachType, int msaaSampleCount, AttachmentInfo*) override;
 
 private:
     HINSTANCE fHInstance;
     HWND      fHWnd;
 };
 
 #endif