Fix sky include guards to match Chromium style

sky/engine/core/dom/shadow/SelectRuleFeatureSet.h

Index: sky/engine/core/dom/shadow/SelectRuleFeatureSet.h
diff --git a/sky/engine/core/dom/shadow/SelectRuleFeatureSet.h b/sky/engine/core/dom/shadow/SelectRuleFeatureSet.h
index bbae2cc0b1e833ac0bf5ed151d0061bf6a6b7599..ff432e1ec6cf6b6c4bc3195b129af30daa85b183 100644
--- a/sky/engine/core/dom/shadow/SelectRuleFeatureSet.h
+++ b/sky/engine/core/dom/shadow/SelectRuleFeatureSet.h
@@ -28,8 +28,8 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef SelectRuleFeatureSet_h
-#define SelectRuleFeatureSet_h
+#ifndef SKY_ENGINE_CORE_DOM_SHADOW_SELECTRULEFEATURESET_H_
+#define SKY_ENGINE_CORE_DOM_SHADOW_SELECTRULEFEATURESET_H_
 
 #include "sky/engine/core/css/RuleFeature.h"
 #include "sky/engine/core/dom/Element.h"
@@ -78,4 +78,4 @@ inline bool SelectRuleFeatureSet::hasSelectorForAttribute(const AtomicString& at
 
 }
 
-#endif
+#endif  // SKY_ENGINE_CORE_DOM_SHADOW_SELECTRULEFEATURESET_H_