Remove support for cap_user_stylesheet

All supported browsers support user stylesheets, and in any case
filter list maintainers shouldn't have to worry about whether
user stylesheets are supported or not.

Author: gorhill

platform/common/vapi-background.js

@@ -41,8 +41,6 @@ if ( vAPI.canWASM === false ) {
     vAPI.canWASM = csp !== undefined && csp.indexOf("'wasm-unsafe-eval'") !== -1;
 }
 
-vAPI.supportsUserStylesheets = vAPI.webextFlavor.soup.has('user_stylesheet');
-
 /******************************************************************************/
 
 vAPI.app = {
@@ -342,14 +340,9 @@ vAPI.Tabs = class {
     }
 
     async insertCSS(tabId, details) {
-        if ( vAPI.supportsUserStylesheets ) {
-            details.cssOrigin = 'user';
-        }
-        try {
-            await webext.tabs.insertCSS(...arguments);
-        }
-        catch {
-        }
+        details.cssOrigin = 'user';
+        try { await webext.tabs.insertCSS(...arguments); }
+        catch { }
     }
 
     async query(queryInfo) {
@@ -363,14 +356,9 @@ vAPI.Tabs = class {
     }
 
     async removeCSS(tabId, details) {
-        if ( vAPI.supportsUserStylesheets ) {
-            details.cssOrigin = 'user';
-        }
-        try {
-            await webext.tabs.removeCSS(...arguments);
-        }
-        catch {
-        }
+        details.cssOrigin = 'user';
+        try { await webext.tabs.removeCSS(...arguments); }
+        catch { }
     }
 
     // Properties of the details object:

platform/common/vapi-common.js

@@ -186,15 +186,13 @@ vAPI.webextFlavor = {
     flavor.isGecko = extensionOrigin.startsWith('moz-extension://');
     if ( flavor.isGecko ) {
         soup.add('firefox')
-            .add('user_stylesheet')
             .add('html_filtering');
         const match = /Firefox\/(\d+)/.exec(ua);
         flavor.major = match && parseInt(match[1], 10) || 115;
     } else {
         const match = /\bChrom(?:e|ium)\/(\d+)/.exec(ua);
         if ( match !== null ) {
-            soup.add('chromium')
-                .add('user_stylesheet');
+            soup.add('chromium');
         }
         flavor.major = match && parseInt(match[1], 10) || 120;
         // Brave can't be told apart through the user agent string, which is

platform/mv3/extension/js/offscreen/compile-filters.js

@@ -327,7 +327,6 @@ async function updateList(list) {
             'mv3',
             'ublock',
             'ubol',
-            'user_stylesheet',
         ],
     };
     const asset = { urls: [ list.id ] };

platform/mv3/make-rulesets.js

@@ -82,7 +82,6 @@ const env = [
     'mv3',
     'ublock',
     'ubol',
-    'user_stylesheet',
     ...envExtra,
 ];
 

src/js/static-filtering-parser.js

@@ -4240,7 +4240,6 @@ export const utils = (( ) => {
         [ 'env_mv3', 'mv3' ],
         [ 'env_safari', 'safari' ],
         [ 'cap_html_filtering', 'html_filtering' ],
-        [ 'cap_user_stylesheet', 'user_stylesheet' ],
         [ 'cap_ipaddress', 'ipaddress' ],
         [ 'false', 'false' ],
         // Hoping ABP-only list maintainers can at least make use of it to