[DevTools] implement isSpaceOrNewline for the STL string wrapper.

third_party/WebKit/Source/platform/inspector_protocol/String16STL.h

 // Copyright 2016 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 String16STL_h
 #define String16STL_h
 
+#include <cctype>
 #include <cstdlib>
 #include <cstring>
 #include <stdint.h>
 #include <string>
 #include <vector>
 
 using UChar = uint16_t;
 using UChar32 = uint32_t;
 using LChar = unsigned char;
 // presubmit: allow wstring
@@ skipping 116 matching lines @@
     static std::string intToString(int);
     static std::string doubleToString(double);
     // presubmit: allow wstring
     wstring m_impl;
     mutable bool has_hash = false;
     mutable std::size_t hash_code = 0;
 };
 
 static inline bool isSpaceOrNewline(UChar c)
 {
-    return false;
+    return std::isspace(c);  // NOLINT
 }
 
 class String16Builder {
 public:
     String16Builder() { }
 
     void append(const String16& str)
     {
         m_impl += str.impl();
     }
@@ skipping 98 matching lines @@
     }
 };
 
 } // namespace std
 
 #endif // !defined(__APPLE__) || defined(_LIBCPP_VERSION)
 
 using String = WTF::String;
 
 #endif // !defined(String16STL_h)