style: Implement inverted-colors media feature

Implemented the inverted-colors media feature from Media Queries Level 5
for all platforms.
Spec: https://drafts.csswg.org/mediaqueries-5/#inverted

Platform specific implementations:
- Windows: Checks system color filter setting, and if it is inverted
  (note: Windows does not live update due to having to read a reg key)
- Mac: Checks dedicated inverted accessibility system setting
- Android: Checks dedicated inverted system setting
- Linux: No GTK API exposes anything like it so always none

Locked behind new pref `layout.css.inverted-colors.enabled`,
always off by default for now.

Also added new WPT tests (none previously).

Other browsers:
- WebKit: shipped since Safari 9.1 (Jan 2017)
- Blink: no signal

Test page: https://goose.icu/inverted-colors

Differential Revision: https://phabricator.services.mozilla.com/D173201

components/style/queries/feature_expression.rs

@@ -329,6 +329,13 @@ fn disabled_by_pref(feature: &Atom, context: &ParserContext) -> bool {
             return !context.in_ua_or_chrome_sheet() &&
                 !static_prefs::pref!("layout.css.prefers-reduced-transparency.enabled");
         }
+
+        // inverted-colors is always enabled in the ua and chrome. On
+        // the web it is hidden behind a preferenc.
+        if *feature == atom!("inverted-colors") {
+            return !context.in_ua_or_chrome_sheet() &&
+                !static_prefs::pref!("layout.css.inverted-colors.enabled");
+        }
     }
     false
 }