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

chrome/browser/media/router/browser_presentation_connection_proxy.h

Index: chrome/browser/media/router/browser_presentation_connection_proxy.h
diff --git a/chrome/browser/media/router/browser_presentation_connection_proxy.h b/chrome/browser/media/router/browser_presentation_connection_proxy.h
index 3fb07ec3b628afcd0b338495d4671b06c86af17b..7f47becacaf17332734d618194b2ac3946681698 100644
--- a/chrome/browser/media/router/browser_presentation_connection_proxy.h
+++ b/chrome/browser/media/router/browser_presentation_connection_proxy.h
@@ -62,6 +62,10 @@ class BrowserPresentationConnectionProxy
   // support state change.
   void DidChangeState(content::PresentationConnectionState state) override {}
 
+  // Underlying media route is always connected. Media route class does not
+  // support state change.
+  void OnClose() override {}
+
  private:
   // |router_| not owned by this class.
   MediaRouter* const router_;