chromium/src/third_party/blink/web_tests/inspector-protocol/emulation/device-emulation-cpu-throttling-multiple.js

(async function(testRunner) {
  testRunner.log('Tests that enabling CPU throttling in multiple pages does not crash.');

  const page1 = await testRunner.createPage();
  const session1 = await page1.createSession();
  await session1.protocol.Target.setDiscoverTargets({discover: true});

  session1.evaluate(`window.open('about:blank') && true`);

  const response = await session1.protocol.Target.onceTargetCreated();
  var page2 = new TestRunner.Page(testRunner, response.params.targetInfo.targetId);
  var session2 = await page2.createSession();

  await session1.protocol.Emulation.setCPUThrottlingRate({rate: 2.0});
  await session2.protocol.Emulation.setCPUThrottlingRate({rate: 3.0});

  testRunner.completeTest();
})