[DevTools] Support multiple sessions in Target domain

third_party/WebKit/LayoutTests/inspector-protocol/worker/exception-from-worker-contains-stack.js

 (async function(testRunner) {
   let {page, session, dp} = await testRunner.startBlank('Tests that console message from worker contains stack trace.');
 
   var workerRequestId = 1;
-  function sendCommandToWorker(method, params, workerId) {
+  function sendCommandToWorker(method, params, workerSessionId) {
     dp.Target.sendMessageToTarget({
-      targetId: workerId,
+      sessionId: workerSessionId,
       message: JSON.stringify({ method: method, params: params, id: workerRequestId++ })
     });
   }
 
   var waitForWorkers = 2;
   dp.Target.onAttachedToTarget(messageObject => {
-    var workerId = messageObject['params']['targetInfo']['targetId'];
+    var workerSessionId = messageObject.params.sessionId;
     testRunner.log('Worker created');
-    sendCommandToWorker('Runtime.enable', {}, workerId);
+    sendCommandToWorker('Runtime.enable', {}, workerSessionId);
     if (!--waitForWorkers)
       session.evaluate('worker1.postMessage(239);worker2.postMessage(42);');
   });
 
   var workerTerminated = false;
   var messageReceived = false;
   dp.Target.onReceivedMessageFromTarget(messageObject => {
     var message = JSON.parse(messageObject['params']['message']);
     if (message['method'] === 'Runtime.exceptionThrown') {
       var callFrames = message.params.exceptionDetails.stackTrace ? message.params.exceptionDetails.stackTrace.callFrames : [];
@@ skipping 15 matching lines @@
   await dp.Target.setAutoAttach({autoAttach: true, waitForDebuggerOnStart: false});
   session.evaluate(`
     window.worker1 = new Worker('${testRunner.url('../resources/worker-with-throw.js')}');
     window.worker1.onerror = function(e) {
       e.preventDefault();
       worker1.terminate();
     }
     window.worker2 = new Worker('${testRunner.url('../resources/worker-with-throw.js')}');
   `);
 })