Fix sky include guards to match Chromium style

sky/engine/core/css/CSSValueTestHelper.h

 /*
  * Copyright (c) 2013, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 15 matching lines @@
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 /**
  * Make testing with gtest and gmock nicer by adding pretty print and other
  * helper functions.
  */
 
-#ifndef CSSValueTestHelper_h
-#define CSSValueTestHelper_h
+#ifndef SKY_ENGINE_CORE_CSS_CSSVALUETESTHELPER_H_
+#define SKY_ENGINE_CORE_CSS_CSSVALUETESTHELPER_H_
 
 #include <ostream>
 #include "sky/engine/core/css/CSSPrimitiveValue.h"
 #include "sky/engine/core/css/CSSValue.h"
 
 namespace testing {
 namespace internal {
 
 // gtest tests won't compile with clang when trying to EXPECT_EQ a class that
 // has the "template<typename T> operator T*()" private.
@@ skipping 17 matching lines @@
     *os << typeName << "(" << cssValue.cssText().utf8().data() << ")";
 }
 
 inline void PrintTo(const CSSPrimitiveValue& cssValue, ::std::ostream* os, const char* typeName = "CSSPrimitiveValue")
 {
     PrintTo(static_cast<const CSSValue&>(cssValue), os, typeName);
 }
 
 }
 
-#endif
+#endif  // SKY_ENGINE_CORE_CSS_CSSVALUETESTHELPER_H_