Add new procedural cosmetic filter operator: :matches-media()

Related issue:
- uBlockOrigin/uBlock-issues#2185

The argument must be a valid media query as documented on MDN, i.e.
what appears between the `@media` at-rule and the first opening
curly bracket (including the parentheses when required):
- https://developer.mozilla.org/en-US/docs/Web/CSS/Media_Queries/Using_media_queries

Best practice:

Use `:matches-media()` after plain CSS selectors, if any.

Good:
    example.com###target-1 > .target-2:matches-media((min-width: 800px))

Bad (though this will still work):
    example.com##:matches-media((min-width: 800px)) #target-1 > .target-2

The reason for this is to keep the door open for a future optimisation
where uBO could convert `:matches-media()`-based filters into CSS media
rules injected declaratively in a user stylesheet.

src/js/contentscript-extra.js

@@ -104,15 +104,22 @@ class PSelectorMatchesCSSBeforeTask extends PSelectorMatchesCSSTask {
 }
 PSelectorMatchesCSSBeforeTask.prototype.pseudo = ':before';
 
-class PSelectorMinTextLengthTask extends PSelectorTask {
+class PSelectorMatchesMediaTask extends PSelectorTask {
     constructor(task) {
         super();
-        this.min = task[1];
+        this.mql = window.matchMedia(task[1]);
+        if ( this.mql.media === 'not all' ) { return; }
+        this.mql.addEventListener('change', ( ) => {
+            if ( typeof vAPI !== 'object' ) { return; }
+            if ( vAPI === null ) { return; }
+            const filterer = vAPI.domFilterer && vAPI.domFilterer.proceduralFilterer;
+            if ( filterer instanceof Object === false ) { return; }
+            filterer.onDOMChanged([ null ]);
+        });
     }
     transpose(node, output) {
-        if ( node.textContent.length >= this.min ) {
-            output.push(node);
-        }
+        if ( this.mql.matches === false ) { return; }
+        output.push(node);
     }
 }
 
@@ -132,6 +139,18 @@ class PSelectorMatchesPathTask extends PSelectorTask {
     }
 }
 
+class PSelectorMinTextLengthTask extends PSelectorTask {
+    constructor(task) {
+        super();
+        this.min = task[1];
+    }
+    transpose(node, output) {
+        if ( node.textContent.length >= this.min ) {
+            output.push(node);
+        }
+    }
+}
+
 class PSelectorOthersTask extends PSelectorTask {
     constructor() {
         super();
@@ -322,6 +341,7 @@ class PSelector {
                 [ ':matches-css', PSelectorMatchesCSSTask ],
                 [ ':matches-css-after', PSelectorMatchesCSSAfterTask ],
                 [ ':matches-css-before', PSelectorMatchesCSSBeforeTask ],
+                [ ':matches-media', PSelectorMatchesMediaTask ],
                 [ ':matches-path', PSelectorMatchesPathTask ],
                 [ ':min-text-length', PSelectorMinTextLengthTask ],
                 [ ':not', PSelectorIfNotTask ],

src/js/static-filtering-parser.js

@@ -1581,6 +1581,18 @@ Parser.prototype.SelectorCompiler = class {
         return n;
     }
 
+    compileMediaQuery(s) {
+        if ( typeof self !== 'object' ) { return; }
+        if ( self === null ) { return; }
+        if ( typeof self.matchMedia !== 'function' ) { return; }
+        try {
+            const mql = self.matchMedia(s);
+            if ( mql instanceof self.MediaQueryList === false ) { return; }
+            if ( mql.media !== 'not all' ) { return s; }
+        } catch(ex) {
+        }
+    }
+
     // https://github.com/uBlockOrigin/uBlock-issues/issues/341#issuecomment-447603588
     //   Reject instances of :not() filters for which the argument is
     //   a valid CSS selector, otherwise we would be adversely changing the
@@ -1702,6 +1714,7 @@ Parser.prototype.SelectorCompiler = class {
             case ':spath':
                 raw.push(task[1]);
                 break;
+            case ':matches-media':
             case ':min-text-length':
             case ':others':
             case ':upward':
@@ -1878,6 +1891,8 @@ Parser.prototype.SelectorCompiler = class {
             return this.compileCSSDeclaration(args);
         case ':matches-css-before':
             return this.compileCSSDeclaration(args);
+        case ':matches-media':
+            return this.compileMediaQuery(args);
         case ':matches-path':
             return this.compileText(args);
         case ':min-text-length':
@@ -1918,7 +1933,8 @@ Parser.prototype.proceduralOperatorTokens = new Map([
     [ 'matches-css', 0b11 ],
     [ 'matches-css-after', 0b11 ],
     [ 'matches-css-before', 0b11 ],
-    [ 'matches-path', 0b01 ],
+    [ 'matches-media', 0b11 ],
+    [ 'matches-path', 0b11 ],
     [ 'min-text-length', 0b01 ],
     [ 'not', 0b01 ],
     [ 'nth-ancestor', 0b00 ],