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

components/test_runner/test_common.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 COMPONENTS_TEST_RUNNER_TEST_COMMON_H_
 #define COMPONENTS_TEST_RUNNER_TEST_COMMON_H_
 
 #include <string>
 
+#include "base/strings/string_util.h"
 #include "components/test_runner/test_runner_export.h"
 #include "third_party/WebKit/public/web/WebNavigationPolicy.h"
 
 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) {
   return !IsASCIIAlpha(ch);
 }
 
 TEST_RUNNER_EXPORT std::string NormalizeLayoutTestURL(const std::string& url);
 
 std::string URLDescription(const GURL& url);
 const char* WebNavigationPolicyToString(
     const blink::WebNavigationPolicy& policy);
 
 // Tests which depend on Blink must call this function on the main thread
 // before creating/calling any Blink objects/APIs.
 TEST_RUNNER_EXPORT void EnsureBlinkInitialized();
 
 }  // namespace test_runner
 
 #endif  // COMPONENTS_TEST_RUNNER_TEST_COMMON_H_