Update web-platform-tests to revision 0f31ab1b094596062154092307bb9ff8e6122533

tests/wpt/web-platform-tests/css/mediaqueries/resources/matchmedia-utils.js

@@ -0,0 +1,49 @@
+'use strict';
+
+function query_is_css_parseable(query) {
+  const style = document.createElement('style');
+  style.type = 'text/css';
+  document.head.appendChild(style);
+
+  const sheet = style.sheet;
+  try {
+    sheet.insertRule("@media " + query + "{}", 0);
+    return sheet.cssRules.length == 1 &&
+        sheet.cssRules[0].media.mediaText != "not all";
+  } finally {
+    while (sheet.cssRules.length)
+      sheet.deleteRule(0);
+    style.remove();
+  }
+}
+
+function query_should_be_css_parseable(query) {
+  test(() => {
+    assert_true(query_is_css_parseable(query));
+  }, "Should be parseable in a CSS stylesheet: '" + query + "'");
+}
+
+function query_should_not_be_css_parseable(query) {
+  test(() => {
+    assert_false(query_is_css_parseable(query));
+  }, "Should not be parseable in a CSS stylesheet: '" + query + "'");
+}
+
+function query_is_js_parseable(query) {
+  // We cannot rely on whether a given feature is on or off, so only check the
+  // 'media' member of the result.
+  const match = window.matchMedia(query);
+  return match.media == query;
+}
+
+function query_should_be_js_parseable(query) {
+  test(() => {
+    assert_true(query_is_js_parseable(query));
+  }, "Should be parseable in JS: '" + query + "'");
+}
+
+function query_should_not_be_js_parseable(query) {
+  test(() => {
+    assert_false(query_is_js_parseable(query));
+  }, "Should not be parseable in JS: '" + query + "'");
+}