[PresentationAPI] Added on-session-text-message handler.

Source/modules/presentation/PresentationSession.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 "config.h"
 #include "modules/presentation/PresentationSession.h"
 
 #include "core/dom/DOMArrayBuffer.h"
 #include "core/dom/DOMArrayBufferView.h"
 #include "core/dom/Document.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/events/Event.h"
+#include "core/events/MessageEvent.h"
 #include "core/frame/LocalFrame.h"
 #include "modules/EventTargetModules.h"
 #include "modules/presentation/Presentation.h"
 #include "modules/presentation/PresentationController.h"
 #include "public/platform/modules/presentation/WebPresentationSessionClient.h"
 #include "wtf/Assertions.h"
 #include "wtf/OwnPtr.h"
 #include "wtf/text/AtomicString.h"
 
 namespace blink {
@@ skipping 105 matching lines @@
     if (m_state == WebPresentationSessionState::Disconnected) {
         throwPresentationDisconnectedError(exceptionState);
         return;
     }
 
     PresentationController* controller = presentationController();
     if (controller)
         controller->send(m_url, m_id, data, size);
 }
 
+void PresentationSession::didReceiveTextMessage(const String& message)
+{
+    dispatchEvent(MessageEvent::create(message));
+}
+
 void PresentationSession::close()
 {
     if (m_state != WebPresentationSessionState::Connected)
         return;
     PresentationController* controller = presentationController();
     if (controller)
         controller->closeSession(m_url, m_id);
 }
 
 bool PresentationSession::matches(WebPresentationSessionClient* client) const
@@ skipping 11 matching lines @@
 }
 
 PresentationController* PresentationSession::presentationController()
 {
     if (!frame())
         return nullptr;
     return PresentationController::from(*frame());
 }
 
 } // namespace blink