[MR tests] Assert initial state / state change for reconnect case.

chrome/test/media_router/resources/common.js

 /**
  * Copyright 2015 The Chromium Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  *
  * @fileoverview Common APIs for presentation integration tests.
  *
  */
 
 var startSessionPromise = null;
@@ skipping 53 matching lines @@
 function checkSession() {
   if (!startSessionPromise) {
     sendResult(false, 'Did not attempt to start session');
   } else {
     startSessionPromise.then(function(session) {
       if(!session) {
         sendResult(false, 'Failed to start session: connection is null');
       } else {
         // set the new session
         startedConnection = session;
-        console.log('connection state is "' + startedConnection.state + '"');
-        if (startedConnection.state == "connected") {
-          sendResult(true, '');
-        } else if (startedConnection.state == "connecting") {
-          startedConnection.onconnect = () => {
-            sendResult(true, '');
-          };
-        } else {
-          sendResult(false,
-            'Expect connection state to be "connecting" or "connected", ' +
-            'actual "' + startedConnection.state + '"');
-        }
+        waitForConnectedStateAndSendResult(startedConnection);
       }
     }).catch(function(e) {
       // terminate old session if exists
       startedConnection && startedConnection.terminate();
       sendResult(false, 'Failed to start session: encountered exception ' + e);
     })
   }
 }
 
 /**
+ * Asserts the current state of the connection is 'connected' or 'connecting'.
+ * If the current state is connecting, waits for it to become 'connected'.
+ * @param {!PresentationConnection} connection
+ */
+function waitForConnectedStateAndSendResult(connection) {
+  console.log(`connection state is "${connection.state}"`);
+  if (connection.state == 'connected') {
+    sendResult(true, '');
+  } else if (connection.state == 'connecting') {
+    connection.onconnect = () => {
+      sendResult(true, '');
+    };
+  } else {
+    sendResult(false,
+      `Expect connection state to be "connecting" or "connected", actual: \
+      "${connection.state}"`);
+  }
+}
+
+/**
  * Checks the start() request fails with expected error and message substring.
  * @param {!string} expectedErrorName
  * @param {!string} expectedErrorMessageSubstring
  */
 function checkStartFailed(expectedErrorName, expectedErrorMessageSubstring) {
   if (!startSessionPromise) {
     sendResult(false, 'Did not attempt to start session');
   } else {
     startSessionPromise.then(function(session) {
       sendResult(false, 'start() unexpectedly succeeded.');
@@ skipping 71 matching lines @@
  * Reconnects to |sessionId| and verifies that it succeeds.
  * @param {!string} sessionId ID of session to reconnect.
  */
 function reconnectSession(sessionId) {
   var reconnectSessionRequest = new PresentationRequest(presentationUrl);
   reconnectSessionRequest.reconnect(sessionId).then(function(session) {
     if (!session) {
       sendResult(false, 'reconnectSession returned null session');
     } else {
       reconnectedSession = session;
-      sendResult(true, '');
+      waitForConnectedStateAndSendResult(reconnectedSession);
     }
   }).catch(function(error) {
     sendResult(false, 'reconnectSession failed: ' + error.message);
   });
 }
 
 /**
  * Calls reconnect(sessionId) and verifies that it fails.
  * @param {!string} sessionId ID of session to reconnect.
  * @param {!string} expectedErrorMessage
@@ skipping 25 matching lines @@
       passed: passed,
       errorMessage: errorMessage
     }));
   } else {
     lastExecutionResult = JSON.stringify({
       passed: passed,
       errorMessage: errorMessage
     });
   }
 }