[DevTools] Migrate inspector-protocol/debugger tests to new harness

third_party/WebKit/LayoutTests/inspector-protocol/debugger/postMessage-on-pause.js

+(async function(testRunner) {
+  let {page, session, dp} = await testRunner.startBlank('');
+
+  dp.Debugger.enable();
+  dp.Runtime.evaluate({expression: `
+    var messageDispatched = false;
+    window.addEventListener('message', event => {
+      messageDispatched = true;
+      debugger;
+    }, true);
+
+    (function testFunction() {
+      window.postMessage('test', '*');
+      debugger;
+    })()
+  `});
+
+  await dp.Debugger.oncePaused();
+  testRunner.log(`Paused on 'debugger;'`);
+
+  var messageObject = await dp.Runtime.evaluate({expression: 'messageDispatched' });
+  var r = messageObject.result.result;
+  if (r.type === 'boolean' && r.value === false)
+    testRunner.log('PASS: message has not been dispatched yet.');
+  else
+    testRunner.log('FAIL: unexpected response ' + JSON.stringify(messageObject, null, 2));
+
+  messageObject = await dp.Runtime.evaluate({expression: 'messageDispatched' });
+  r = messageObject.result.result;
+  if (r.type === 'boolean' && r.value === false)
+    testRunner.log('PASS: message has not been dispatched yet.');
+  else
+    testRunner.log('FAIL: unexpected response ' + JSON.stringify(messageObject, null, 2));
+
+  await dp.Debugger.resume();
+  testRunner.log('Resumed, now waiting for pause in the event listener...');
+
+  await dp.Debugger.oncePaused();
+  testRunner.log('PASS: pasued in the event listener.');
+  await dp.Debugger.resume();
+  testRunner.completeTest();
+})