Fix sky include guards to match Chromium style

sky/engine/core/css/PointerProperties.h

 // Copyright 2014 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 PointerProperties_h
-#define PointerProperties_h
+#ifndef SKY_ENGINE_CORE_CSS_POINTERPROPERTIES_H_
+#define SKY_ENGINE_CORE_CSS_POINTERPROPERTIES_H_
 
 namespace blink {
 
 // The values of these enums must match their corresponding enums in
 // WebSettings.h.
 
 // Used as a bitfield so enums must be powers of 2.
 enum PointerType {
     PointerTypeNone = 1,
     PointerTypeCoarse = 2,
     PointerTypeFine = 4
 };
 
 // Used as a bitfield so enums must be powers of 2.
 enum HoverType {
     HoverTypeNone = 1,
     // Indicates that the primary pointing system can hover, but it requires
     // a significant action on the user’s part. e.g. hover on “long press”.
     HoverTypeOnDemand = 2,
     HoverTypeHover = 4
 };
 
 }
 
-#endif
+#endif  // SKY_ENGINE_CORE_CSS_POINTERPROPERTIES_H_