WebUI: Wrap OS preferred font name with quotes.

This is necessary to ensure that the font name will be correctly
parsed in CSS, even when it contains a number or punctuation mark.

Fixed: 1128566
Change-Id: Ia4159483cac30a350eabaddaf5142fd58a9bd299
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2456633
Commit-Queue: dpapad <dpapad@chromium.org>
Reviewed-by: Dominik Röttsches <drott@chromium.org>
Cr-Commit-Position: refs/heads/master@{#814849}

ui/base/webui/web_ui_util.cc

@@ -230,10 +230,12 @@ std::string GetFontFamily() {
 // into Ozone: crbug.com/320050
 #if defined(OS_LINUX) && !defined(OS_CHROMEOS)
   if (!features::IsUsingOzonePlatform()) {
-    font_family = ui::ResourceBundle::GetSharedInstance()
-                      .GetFont(ui::ResourceBundle::BaseFont)
-                      .GetFontName() +
-                  ", " + font_family;
+    std::string font_name = ui::ResourceBundle::GetSharedInstance()
+                                .GetFont(ui::ResourceBundle::BaseFont)
+                                .GetFontName();
+    // Wrap |font_name| with quotes to ensure it will always be parsed correctly
+    // in CSS.
+    font_family = "\"" + font_name + "\", " + font_family;
   }
 #endif