Bug 1449089 part 3 - Remove pref layout.css.scope-pseudo.enabled. r=emilio

It was never effective in Stylo anyway.

MozReview-Commit-ID: EF7NnS6uxOO

--HG--
extra : rebase_source : 8d924fad9958cf12c746156241c51c3a6488020f

dom/base/test/file_bug416317.xhtml

@@ -227,13 +227,7 @@
   </span>
   <script><![CDATA[
   window.onload = function() {
-    if (window.parent && window.parent.SpecialPowers) {
-      window.parent.SpecialPowers.pushPrefEnv(
-        { 'set': [[ "layout.css.scope-pseudo.enabled", true]] },
-        doTest);
-    } else {
-      doTest();
-    }
+    doTest();
   }
 
   function doTest(){

layout/style/nsCSSPseudoClassList.h

@@ -125,7 +125,7 @@ CSS_PSEUDO_CLASS(mozBrowserFrame, ":-moz-browser-frame",
 
 // Matches whatever the contextual reference elements are for the
 // matching operation.
-CSS_PSEUDO_CLASS(scope, ":scope", 0, "layout.css.scope-pseudo.enabled")
+CSS_PSEUDO_CLASS(scope, ":scope", 0, "")
 
 // :not needs to come at the end of the non-bit pseudo-class list, since
 // it doesn't actually get directly matched on in SelectorMatches.

modules/libpref/init/all.js

@@ -3084,9 +3084,6 @@ pref("layout.css.prefixes.webkit", true);
 // pref is set to false.)
 pref("layout.css.prefixes.device-pixel-ratio-webkit", false);
 
-// Is support for the :scope selector enabled?
-pref("layout.css.scope-pseudo.enabled", true);
-
 // Is support for background-blend-mode enabled?
 pref("layout.css.background-blend-mode.enabled", true);