1 files changed, 29 insertions, 0 deletions
diff --git a/testing/web-platform/tests/timing-entrytypes-registry/resources/utils.js b/testing/web-platform/tests/timing-entrytypes-registry/resources/utils.js
new file mode 100644
index 0000000000..0ec96057ad
--- /dev/null
+++ b/testing/web-platform/tests/timing-entrytypes-registry/resources/utils.js
@@ -0,0 +1,29 @@
+const STEPS = {};
+
+const types = (self.PerformanceObserver
+                  && self.PerformanceObserver.supportedEntryTypes)?
+    self.PerformanceObserver.supportedEntryTypes
+    : undefined;
+
+if (types) {
+  // we observe everything as soon as possible
+  new PerformanceObserver(function (list, observer) {
+    for (const entry of list.getEntries())
+      if (STEPS[entry.entryType]) STEPS[entry.entryType](entry);
+  }).observe({entryTypes: self.PerformanceObserver.supportedEntryTypes});
+}
+
+function test_support(def) {
+  if (!types || !types.includes(def[0])) {
+    return;
+  }
+  const desc = `'${def[0]}' entries should be observable`;
+  const t = async_test(desc);
+
+  STEPS[def[0]] = (entry) => {
+    t.step(() => assert_equals(Object.prototype.toString.call(entry),
+    `[object ${def[1]}]`,
+    `Class name of entry should be ${def[1]}.`));
+    t.done();
+  }
+}