diff --git a/shell/app/command_line_args.cc b/shell/app/command_line_args.cc
index 3dbc56c1e63..e9d052a8fa4 100644
--- a/shell/app/command_line_args.cc
+++ b/shell/app/command_line_args.cc
@@ -3,13 +3,14 @@
 // found in the LICENSE file.
 
 #include "shell/app/command_line_args.h"
+#include <locale>
 
 namespace {
 
 bool IsUrlArg(const base::CommandLine::CharType* arg) {
   // the first character must be a letter for this to be a URL
   auto c = *arg;
-  if (('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z')) {
+  if (std::isalpha(c, std::locale::classic())) {
     for (auto* p = arg + 1; *p; ++p) {
       c = *p;
 
@@ -23,7 +24,7 @@ bool IsUrlArg(const base::CommandLine::CharType* arg) {
       }
 
       // white-space before a colon means it's not a URL
-      if (c == ' ' || (0x9 <= c && c <= 0xD))
+      if (std::isspace(c, std::locale::classic()))
         break;
     }
   }