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

sql/connection.cc

Index: sql/connection.cc
diff --git a/sql/connection.cc b/sql/connection.cc
index b1be62f586a782d64fca587e671254f912e29493..b17da0dde2f7f00fe199ee72ad37f8dcbadcc5b7 100644
--- a/sql/connection.cc
+++ b/sql/connection.cc
@@ -116,9 +116,8 @@ int BackupDatabase(sqlite3* src, sqlite3* dst, const char* db_name) {
 // just use clean names to start with.
 bool ValidAttachmentPoint(const char* attachment_point) {
   for (size_t i = 0; attachment_point[i]; ++i) {
-    if (!((attachment_point[i] >= '0' && attachment_point[i] <= '9') ||
-          (attachment_point[i] >= 'a' && attachment_point[i] <= 'z') ||
-          (attachment_point[i] >= 'A' && attachment_point[i] <= 'Z') ||
+    if (!(base::IsAsciiDigit(attachment_point[i]) ||
+          base::IsAsciiAlpha(attachment_point[i]) ||
           attachment_point[i] == '_')) {
       return false;
     }