Mojo C++ Bindings: Allow callbacks to own their InterfacePtr

mojo/public/cpp/bindings/lib/interface_endpoint_client.cc

Index: mojo/public/cpp/bindings/lib/interface_endpoint_client.cc
diff --git a/mojo/public/cpp/bindings/lib/interface_endpoint_client.cc b/mojo/public/cpp/bindings/lib/interface_endpoint_client.cc
index 2a02ef202f47455b80875d4a423da1648e7b1614..a6a9c0686bb839f27869ce80a2533e751a749c2c 100644
--- a/mojo/public/cpp/bindings/lib/interface_endpoint_client.cc
+++ b/mojo/public/cpp/bindings/lib/interface_endpoint_client.cc
@@ -280,9 +280,11 @@ void InterfaceEndpointClient::NotifyError() {
     return;
   encountered_error_ = true;
 
-  // The callbacks may hold on to resources. There is no need to keep them any
-  // longer.
-  async_responders_.clear();
+  // Response callbacks may hold on to resource, and there's no need to keep
+  // them alive any longer. Note that it's allowed that a pending response
+  // callback may own this endpoint, so we simply move the responders onto the
+  // stack here and let them be destroyed when the stack unwinds.
+  AsyncResponderMap responders = std::move(async_responders_);
 
   control_message_proxy_.OnConnectionError();