[PresentationAPI] Plumbing |onstatechange| event for the PresentationSession from Blink to platform/

Source/modules/presentation/PresentationController.cpp

Index: Source/modules/presentation/PresentationController.cpp
diff --git a/Source/modules/presentation/PresentationController.cpp b/Source/modules/presentation/PresentationController.cpp
index e16165776cef9fd356f81d69ab16fe8a0e5a526e..5d0a67ad10271ceb1890ff60aa5a849dff899cca 100644
--- a/Source/modules/presentation/PresentationController.cpp
+++ b/Source/modules/presentation/PresentationController.cpp
@@ -86,6 +86,14 @@ void PresentationController::didStartDefaultSession(WebPresentationSessionClient
     m_presentation->didStartDefaultSession(session);
 }
 
+void PresentationController::didChangeSessionState(WebPresentationSessionClient* sessionClient, WebPresentationSessionState state)
+{
+    if (m_presentation)
+        m_presentation->didChangeSessionState(sessionClient, state);
+    else
+        PresentationSession::dispose(sessionClient);
+}
+
 void PresentationController::startSession(const String& presentationUrl, const String& presentationId, WebPresentationSessionClientCallbacks* callbacks)
 {
     if (!m_client) {