Implement IsAsciiUpper and IsAsciiLower in base/strings/string_util.h

components/test_runner/test_common.h

Index: components/test_runner/test_common.h
diff --git a/components/test_runner/test_common.h b/components/test_runner/test_common.h
index d1e758b43b6f7eecc3a4bd16ffc3f9e139409c23..57e9747f989dc570affd66e27d5bd5379defe905 100644
--- a/components/test_runner/test_common.h
+++ b/components/test_runner/test_common.h
@@ -7,6 +7,7 @@
 
 #include <string>
 
+#include "base/strings/string_util.h"
 #include "components/test_runner/test_runner_export.h"
 #include "third_party/WebKit/public/web/WebNavigationPolicy.h"
 
@@ -15,7 +16,7 @@ class GURL;
 namespace test_runner {
 
 inline bool IsASCIIAlpha(char ch) {
-  return (ch | 0x20) >= 'a' && (ch | 0x20) <= 'z';
+  return base::IsAsciiLower(ch | 0x20);
 }
 
 inline bool IsNotASCIIAlpha(char ch) {