[Presentation API] Adds close method to Presentation session.

Source/modules/presentation/PresentationSession.cpp

Index: Source/modules/presentation/PresentationSession.cpp
diff --git a/Source/modules/presentation/PresentationSession.cpp b/Source/modules/presentation/PresentationSession.cpp
index 03ac8d4cb0c029fe14854bc4e4bdaa7b1d9f7dd3..17d11d37fbae0a849476113209118d1de45028bf 100644
--- a/Source/modules/presentation/PresentationSession.cpp
+++ b/Source/modules/presentation/PresentationSession.cpp
@@ -9,6 +9,7 @@
 #include "core/frame/LocalFrame.h"
 #include "modules/EventTargetModules.h"
 #include "modules/presentation/Presentation.h"
+#include "modules/presentation/PresentationController.h"
 #include "public/platform/WebString.h"
 #include "public/platform/modules/presentation/WebPresentationSessionClient.h"
 #include "wtf/OwnPtr.h"
@@ -67,6 +68,17 @@ void PresentationSession::postMessage(const String& message)
 
 void PresentationSession::close()
 {
+    PresentationController* controller = presentationController();
+    if (controller) {

[whywhat, 2015/03/17 23:35:19]

nit: remove the braces

[haibinlu, 2015/03/18 00:58:22]

Done.

+        controller->closeSession(m_id);
+    }
+}
+
+PresentationController* PresentationSession::presentationController()
+{
+    if (!frame())
+        return nullptr;
+    return PresentationController::from(*frame());
 }
 
 } // namespace blink