Fix sky include guards to match Chromium style

sky/engine/core/animation/Keyframe.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 Keyframe_h
-#define Keyframe_h
+#ifndef SKY_ENGINE_CORE_ANIMATION_KEYFRAME_H_
+#define SKY_ENGINE_CORE_ANIMATION_KEYFRAME_H_
 
 #include "gen/sky/core/CSSPropertyNames.h"
 #include "sky/engine/core/animation/AnimationEffect.h"
 #include "sky/engine/core/animation/AnimationNode.h"
 #include "sky/engine/core/animation/animatable/AnimatableValue.h"
 
 namespace blink {
 
 typedef HashSet<CSSPropertyID> PropertySet;
 
@@ skipping 71 matching lines @@
     {
     }
 
     double m_offset;
     AnimationEffect::CompositeOperation m_composite;
     RefPtr<TimingFunction> m_easing;
 };
 
 }
 
-#endif
+#endif  // SKY_ENGINE_CORE_ANIMATION_KEYFRAME_H_