Fix sky include guards to match Chromium style

sky/engine/core/css/CSSCalculationValue.h

Index: sky/engine/core/css/CSSCalculationValue.h
diff --git a/sky/engine/core/css/CSSCalculationValue.h b/sky/engine/core/css/CSSCalculationValue.h
index 3f3c69551aace5a7499d7fb9b9e1b7edc2054e4e..bae892398421b9ff4dca5eb018aad4367cca8ff6 100644
--- a/sky/engine/core/css/CSSCalculationValue.h
+++ b/sky/engine/core/css/CSSCalculationValue.h
@@ -28,8 +28,8 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef CSSCalculationValue_h
-#define CSSCalculationValue_h
+#ifndef SKY_ENGINE_CORE_CSS_CSSCALCULATIONVALUE_H_
+#define SKY_ENGINE_CORE_CSS_CSSCALCULATIONVALUE_H_
 
 #include "sky/engine/core/css/CSSPrimitiveValue.h"
 #include "sky/engine/core/css/CSSValue.h"
@@ -147,4 +147,4 @@ DEFINE_CSS_VALUE_TYPE_CASTS(CSSCalcValue, isCalcValue());
 } // namespace blink
 
 
-#endif // CSSCalculationValue_h
+#endif  // SKY_ENGINE_CORE_CSS_CSSCALCULATIONVALUE_H_