Add more information for web test runner on Windows

When using Korean as display language, web test runner doesn't
work. Let people know this with error string.

Bug: None
Change-Id: I96e2454699db827c3e8f373a401658082de2a095
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2364345
Commit-Queue: Peter Beverloo <peter@chromium.org>
Reviewed-by: Peter Beverloo <peter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#799907}

content/shell/browser/web_test/web_test_browser_main_platform_support_win.cc

@@ -67,7 +67,9 @@ bool WebTestBrowserCheckLayoutSystemDeps() {
   for (size_t i = 0; i < base::size(system_fonts); ++i) {
     if (system_fonts[i]->lfHeight != required_font_size ||
         wcscmp(required_font, system_fonts[i]->lfFaceName)) {
-      errors.push_back("Must use either the Aero or Basic theme.");
+      errors.push_back(
+          "Must use either the Aero or Basic theme. Or change display language "
+          "to English.");
       break;
     }
   }