Presentation API: implement renderer side of PresentationConnection.close().

content/renderer/presentation/presentation_dispatcher.h

Index: content/renderer/presentation/presentation_dispatcher.h
diff --git a/content/renderer/presentation/presentation_dispatcher.h b/content/renderer/presentation/presentation_dispatcher.h
index 1bf5559756025cc573d5d90b0277f89d20aecee4..1ee061ed29a8d54c4bcea79899c86b7bcb4251f6 100644
--- a/content/renderer/presentation/presentation_dispatcher.h
+++ b/content/renderer/presentation/presentation_dispatcher.h
@@ -76,6 +76,8 @@ class CONTENT_EXPORT PresentationDispatcher
                     const blink::WebString& presentationId,
                     const uint8* data,
                     size_t length) override;
+  void closeSession(const blink::WebString& presentationUrl,
+                    const blink::WebString& presentationId) override;
   void terminateSession(const blink::WebString& presentationUrl,
                         const blink::WebString& presentationId) override;
   void getAvailability(