[Media Router] 2nd take on fix route response callback lifetime in UI.

chrome/browser/media/router/create_session_request.cc

Index: chrome/browser/media/router/create_session_request.cc
diff --git a/chrome/browser/media/router/create_session_request.cc b/chrome/browser/media/router/create_session_request.cc
index c9516cd7e0b43cbea6420fc3e2a98fd9bb0a93f4..29e6226ed241a5be29fa393a086538f01ae16ea1 100644
--- a/chrome/browser/media/router/create_session_request.cc
+++ b/chrome/browser/media/router/create_session_request.cc
@@ -26,6 +26,10 @@ CreateSessionRequest::CreateSessionRequest(
 }
 
 CreateSessionRequest::~CreateSessionRequest() {
+  if (!cb_invoked_) {
+    error_cb_.Run(content::PresentationError(
+        content::PRESENTATION_ERROR_UNKNOWN, "Unknown error."));
+  }
 }
 
 void CreateSessionRequest::MaybeInvokeSuccessCallback(