Bug 1685917 - Remove layout.css.file-selector-button.enabled pref. r=heycam

On by default since bug 1662478 (Firefox 82)

Depends on D101289

Differential Revision: https://phabricator.services.mozilla.com/D101290

browser/base/content/test/static/browser_parsable_css.js

@@ -92,22 +92,13 @@ if (
   });
 }
 
-if (Services.prefs.getBoolPref("layout.css.file-selector-button.enabled")) {
-  // System colors reserved to UA / chrome sheets
-  whitelist.push({
-    sourceName: /(?:res|gre-resources)\/forms\.css$/i,
-    errorMessage: /Expected color but found \u2018-moz.*/i,
-    platforms: ["linux"],
-    isFromDevTools: false,
-  });
-} else {
-  // Reserved to UA sheets, behind a pref for content.
-  whitelist.push({
-    sourceName: /(?:res|gre-resources)\/forms\.css$/i,
-    errorMessage: /Unknown pseudo-.*file-selector-button/i,
-    isFromDevTools: false,
-  });
-}
+// System colors reserved to UA / chrome sheets
+whitelist.push({
+  sourceName: /(?:res|gre-resources)\/forms\.css$/i,
+  errorMessage: /Expected color but found \u2018-moz.*/i,
+  platforms: ["linux"],
+  isFromDevTools: false,
+});
 
 if (!Services.prefs.getBoolPref("layout.css.autofill.enabled")) {
   // Reserved to UA sheets, behind a pref for content.

layout/style/nsCSSPseudoElementList.h

@@ -92,5 +92,4 @@ CSS_PSEUDO_ELEMENT(mozTextControlPreview, ":-moz-text-control-preview",
                    CSS_PSEUDO_ELEMENT_ENABLED_IN_UA_SHEETS)
 
 CSS_PSEUDO_ELEMENT(fileSelectorButton, ":file-selector-button",
-                   CSS_PSEUDO_ELEMENT_ENABLED_IN_UA_SHEETS |
                    CSS_PSEUDO_ELEMENT_SUPPORTS_USER_ACTION_STATE)

layout/style/nsCSSPseudoElements.h

@@ -119,13 +119,8 @@ class nsCSSPseudoElements {
   }
 
   static bool EnabledInContent(Type aType) {
-    switch (aType) {
-      case Type::fileSelectorButton:
-        return mozilla::StaticPrefs::layout_css_file_selector_button_enabled();
-      default:
-        return !PseudoElementHasAnyFlag(
-            aType, CSS_PSEUDO_ELEMENT_ENABLED_IN_UA_SHEETS_AND_CHROME);
-    }
+    return !PseudoElementHasAnyFlag(
+        aType, CSS_PSEUDO_ELEMENT_ENABLED_IN_UA_SHEETS_AND_CHROME);
   }
 
   static bool IsEnabled(Type aType, EnabledState aEnabledState) {

modules/libpref/init/StaticPrefList.yaml

@@ -6740,13 +6740,6 @@
   value: true
   mirror: always
 
-# Is support for the ::file-selector-button pseudo-element enabled?
-- name: layout.css.file-selector-button.enabled
-  type: RelaxedAtomicBool
-  value: true
-  mirror: always
-  rust: true
-
 # Whether the computed value of line-height: normal returns the `normal`
 # keyword rather than a pixel value based on the first available font.
 #

servo/components/style/gecko/pseudo_element.rs

@@ -160,12 +160,7 @@ impl PseudoElement {
 
     /// Whether this pseudo-element is enabled for all content.
     pub fn enabled_in_content(&self) -> bool {
-        match *self {
-            PseudoElement::FileSelectorButton => {
-                static_prefs::pref!("layout.css.file-selector-button.enabled")
-            },
-            _ => (self.flags() & structs::CSS_PSEUDO_ELEMENT_ENABLED_IN_UA_SHEETS_AND_CHROME) == 0,
-        }
+        self.flags() & structs::CSS_PSEUDO_ELEMENT_ENABLED_IN_UA_SHEETS_AND_CHROME == 0
     }
 
     /// Whether this pseudo is enabled explicitly in UA sheets.