[Presentation API] Use connection proxy to change connection state to 'closed'

content/renderer/presentation/presentation_connection_proxy.h

Index: content/renderer/presentation/presentation_connection_proxy.h
diff --git a/content/renderer/presentation/presentation_connection_proxy.h b/content/renderer/presentation/presentation_connection_proxy.h
index 6c70527704316e552fb0dd1acb8e447d30462f28..7eb60f281bc51cdea7e56346bec3468b326a07fc 100644
--- a/content/renderer/presentation/presentation_connection_proxy.h
+++ b/content/renderer/presentation/presentation_connection_proxy.h
@@ -82,6 +82,10 @@ class CONTENT_EXPORT PresentationConnectionProxy
   void OnMessage(blink::mojom::ConnectionMessagePtr message,
                  const OnMessageCallback& callback) override;
   void DidChangeState(content::PresentationConnectionState state) override;
+  void OnClose() override;
+
+  // blink::WebPresentationConnectionProxy implementation.
+  void close() const override;
 
  protected:
   explicit PresentationConnectionProxy(