Bug 1778429, use utf-16 character literals when calling ReplaceChar in SanitizeFileName, r=Gijs

Differential Revision: https://phabricator.services.mozilla.com/D152669

uriloader/exthandler/nsExternalHelperAppService.cpp

@@ -3504,8 +3504,8 @@ void nsExternalHelperAppService::SanitizeFileName(nsAString& aFileName,
   nsAutoString fileName(aFileName);
 
   // Replace known invalid characters.
-  fileName.ReplaceChar(KNOWN_PATH_SEPARATORS, '_');
-  fileName.ReplaceChar(FILE_ILLEGAL_CHARACTERS, ' ');
+  fileName.ReplaceChar(u"" KNOWN_PATH_SEPARATORS, '_');
+  fileName.ReplaceChar(u"" FILE_ILLEGAL_CHARACTERS, ' ');
   fileName.StripChar(char16_t(0));
 
   const char16_t *startStr, *endStr;

uriloader/exthandler/tests/unit/test_filename_sanitize.js

@@ -150,4 +150,13 @@ add_task(async function validate_filename_method() {
     checkFilename(repeatStr + ext, mimeService.VALIDATE_SANITIZE_ONLY),
     repeatStr.substring(0, 234) + ".long_invalid% ch_ars"
   );
+
+  Assert.equal(
+    checkFilename("test_ﾃｽﾄ_T\x83E\\S\x83T.png", 0),
+    "test_ﾃｽﾄ_T E_S T.png"
+  );
+  Assert.equal(
+    checkFilename("test_ﾃｽﾄ_T\x83E\\S\x83T.pﾃ\x83ng", 0),
+    "test_ﾃｽﾄ_T E_S T.png"
+  );
 });