Fix sky include guards to match Chromium style

sky/engine/core/page/PageAnimator.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 PageAnimator_h
-#define PageAnimator_h
+#ifndef SKY_ENGINE_CORE_PAGE_PAGEANIMATOR_H_
+#define SKY_ENGINE_CORE_PAGE_PAGEANIMATOR_H_
 
 namespace blink {
 
 class LocalFrame;
 class Page;
 
 class PageAnimator {
 public:
     explicit PageAnimator(Page*);
 
     void scheduleVisualUpdate();
     void serviceScriptedAnimations(double monotonicAnimationStartTime);
 
     void setAnimationFramePending() { m_animationFramePending = true; }
     bool isServicingAnimations() const { return m_servicingAnimations; }
     void updateLayoutAndStyleForPainting(LocalFrame* rootFrame);
 
 private:
     Page* m_page;
     bool m_animationFramePending;
     bool m_servicingAnimations;
     bool m_updatingLayoutAndStyleForPainting;
 };
 
 }
 
-#endif // PageAnimator_h
+#endif  // SKY_ENGINE_CORE_PAGE_PAGEANIMATOR_H_