Replace some hard coded schemes with the constants in /url/url_constants.h.

url/url_util.cc

Index: url/url_util.cc
diff --git a/url/url_util.cc b/url/url_util.cc
index 7cb2de24a86598a76a438f69dd0c34142c626a5a..9f2ad2c69094a90e52b6a70fe2e5ed33af280a05 100644
--- a/url/url_util.cc
+++ b/url/url_util.cc
@@ -35,13 +35,13 @@ inline bool DoLowerCaseEqualsASCII(Iter a_begin, Iter a_end, const char* b) {
 
 const int kNumStandardURLSchemes = 8;
 const char* kStandardURLSchemes[kNumStandardURLSchemes] = {
-  "http",
-  "https",
+  kHttpScheme,
+  kHttpsScheme,
   kFileScheme,  // Yes, file urls can have a hostname!
-  "ftp",
-  "gopher",
-  "ws",  // WebSocket.
-  "wss",  // WebSocket secure.
+  kFtpScheme,
+  kGopherScheme,
+  kWsScheme,    // WebSocket.
+  kWssScheme,   // WebSocket secure.
   kFileSystemScheme,
 };