style: Hide -moz-touch-enabled media query in Nightly and Early Beta.

This is effectively superseded by the hover / any-hover media queries, which actually are standard, and is also causing trouble in the wild. Not even the browser fronted uses it, so we should be able to just remove it everywhere at once. Differential Revision: https://phabricator.services.mozilla.com/D49506
servo · Nov 4, 2019 · b98ac61 · b98ac61
1 parent 7965dde
commit b98ac61
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Showing 3 changed files with 18 additions and 10 deletions.
diff --git a/components/style/gecko/media_features.rs b/components/style/gecko/media_features.rs
@@ -598,8 +598,7 @@ lazy_static! {
             atom!("device-pixel-ratio"),
             AllowsRanges::Yes,
             Evaluator::Float(eval_device_pixel_ratio),
-            ParsingRequirements::WEBKIT_PREFIX |
-                ParsingRequirements::WEBKIT_DEVICE_PIXEL_RATIO_PREF_ENABLED,
+            ParsingRequirements::WEBKIT_PREFIX,
         ),
         // -webkit-transform-3d.
         feature!(

diff --git a/components/style/media_queries/media_feature.rs b/components/style/media_queries/media_feature.rs
@@ -123,9 +123,6 @@ bitflags! {
         const CHROME_AND_UA_ONLY = 1 << 0;
         /// The feature requires a -webkit- prefix.
         const WEBKIT_PREFIX = 1 << 1;
-        /// The feature requires the webkit-device-pixel-ratio preference to be
-        /// enabled.
-        const WEBKIT_DEVICE_PIXEL_RATIO_PREF_ENABLED = 1 << 2;
     }
 }
 

diff --git a/components/style/media_queries/media_feature_expression.rs b/components/style/media_queries/media_feature_expression.rs
@@ -242,6 +242,16 @@ fn consume_operation_or_colon(input: &mut Parser) -> Result<Option<Operator>, ()
     }))
 }
 
+fn disabled_by_pref(feature: &Atom) -> bool {
+    if *feature == atom!("device-pixel-ratio") {
+        return !static_prefs::pref!("layout.css.prefixes.device-pixel-ratio-webkit");
+    }
+    if *feature == atom!("-moz-touch-enabled") {
+        return !static_prefs::pref!("layout.css.moz-touch-enabled.enabled")
+    }
+    false
+}
+
 impl MediaFeatureExpression {
     fn new(
         feature_index: usize,
@@ -301,11 +311,6 @@ impl MediaFeatureExpression {
                     if starts_with_ignore_ascii_case(feature_name, "-webkit-") {
                         feature_name = &feature_name[8..];
                         requirements.insert(ParsingRequirements::WEBKIT_PREFIX);
-                        if static_prefs::pref!("layout.css.prefixes.device-pixel-ratio-webkit") {
-                            requirements.insert(
-                                ParsingRequirements::WEBKIT_DEVICE_PIXEL_RATIO_PREF_ENABLED,
-                            );
-                        }
                     }
                 }
 
@@ -320,6 +325,13 @@ impl MediaFeatureExpression {
                 };
 
                 let atom = Atom::from(string_as_ascii_lowercase(feature_name));
+
+                if disabled_by_pref(&atom) {
+                    return Err(location.new_custom_error(
+                        StyleParseErrorKind::MediaQueryExpectedFeatureName(ident.clone()),
+                    ));
+                }
+
                 match MEDIA_FEATURES
                     .iter()
                     .enumerate()