[Presentation API] Fix race condition in which state change is lost.

third_party/WebKit/Source/modules/presentation/PresentationConnection.cpp

 // Copyright 2014 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.
 
 #include "modules/presentation/PresentationConnection.h"
 
 #include "bindings/core/v8/ScriptPromiseResolver.h"
 #include "core/dom/DOMArrayBuffer.h"
 #include "core/dom/DOMArrayBufferView.h"
 #include "core/dom/Document.h"
@@ skipping 182 matching lines @@
   controller->registerConnection(connection);
 
   // Fire onconnectionavailable event asynchronously.
   auto* event = PresentationConnectionAvailableEvent::create(
       EventTypeNames::connectionavailable, connection);
   request->getExecutionContext()->postTask(
       TaskType::Presentation, BLINK_FROM_HERE,
       createSameThreadTask(&PresentationConnection::dispatchEventAsync,
                            wrapPersistent(request), wrapPersistent(event)));
 
+  // Fire onconnect event asynchronously, after onconnectionavailable.
+  connection->didChangeState(WebPresentationConnectionState::Connected);
+
   return connection;
 }
 
 // static
 PresentationConnection* PresentationConnection::take(
     PresentationReceiver* receiver,
     const WebPresentationSessionInfo& sessionInfo) {
   DCHECK(receiver);
 
   PresentationConnection* connection = new PresentationConnection(
@@ skipping 281 matching lines @@
 void PresentationConnection::tearDown() {
   // Cancel current Blob loading if any.
   if (m_blobLoader) {
     m_blobLoader->cancel();
     m_blobLoader.clear();
   }
   m_messages.clear();
 }
 
 }  // namespace blink