Fix sky include guards to match Chromium style

sky/engine/platform/WindowsKeyboardCodes.h

 /*
  * Copyright (C) 2010 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS "AS IS"
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
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  */
 
+#ifndef SKY_ENGINE_PLATFORM_WINDOWSKEYBOARDCODES_H_
+#define SKY_ENGINE_PLATFORM_WINDOWSKEYBOARDCODES_H_
+
 #ifndef VK_UNKNOWN
 
 #define VK_UNKNOWN 0
 
 // Left mouse button
 // Right mouse button
 // Control-break processing
 // Middle mouse button (three-button mouse)
 // VK_XBUTTON1 (05)
 // VK_XBUTTON2 (06)
@@ skipping 275 matching lines @@
 #define VK_PLAY 0xFA // Play key
 #define VK_ZOOM 0xFB // Zoom key
 
 #define VK_NONAME 0xFC // Reserved for future use
 
 #define VK_PA1 0xFD // VK_PA1 (FD) PA1 key
 
 #define VK_OEM_CLEAR 0xFE // Clear key
 
 #endif // VK_UNKNOWN
+
+#endif  // SKY_ENGINE_PLATFORM_WINDOWSKEYBOARDCODES_H_