1 files changed, 25 insertions, 0 deletions
diff --git a/testing/web-platform/tests/is-input-pending/resources/input-onmessage.js b/testing/web-platform/tests/is-input-pending/resources/input-onmessage.js
new file mode 100644
index 0000000000..919c939d1f
--- /dev/null
+++ b/testing/web-platform/tests/is-input-pending/resources/input-onmessage.js
@@ -0,0 +1,25 @@
+// Responds to onmessage events from other frames to check for pending input.
+onmessage = async e => {
+  if (e.data !== 'check-input') return;
+
+  const discreteOptions = { includeContinuous: false };
+  const continuousOptions = { includeContinuous: true };
+
+  // Use a reasonable time to wait after dispatching events, since we want to be
+  // able to test for cases where isInputPending returns false.
+  const DISPATCH_WAIT_TIME_MS = 500;
+
+  // Wait a reasonable amount of time for the event to be enqueued.
+  const end = performance.now() + DISPATCH_WAIT_TIME_MS;
+  let hasDiscrete;
+  let hasContinuous;
+  do {
+    hasDiscrete = navigator.scheduling.isInputPending(discreteOptions);
+    hasContinuous = navigator.scheduling.isInputPending(continuousOptions);
+  } while (performance.now() < end && !(hasDiscrete && hasContinuous));
+
+  e.source.postMessage({
+    discrete: hasDiscrete,
+    continuous: hasContinuous,
+  }, '*');
+}