Monitor the ShellClient binding for pipe closure as a signal to shut down the ShellConnection, rath…

mojo/shell/public/cpp/lib/connector_impl.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "mojo/shell/public/cpp/lib/connector_impl.h"
 
 #include "mojo/shell/public/cpp/lib/connection_impl.h"
 
 namespace mojo {
 
 Connector::ConnectParams::ConnectParams(const std::string& name)
     : name_(name),
       user_id_(shell::mojom::Connector::kUserInherit) {
 }
 Connector::ConnectParams::~ConnectParams() {}
 
 ConnectorImpl::ConnectorImpl(shell::mojom::ConnectorPtrInfo unbound_state)
     : unbound_state_(std::move(unbound_state)) {}
-ConnectorImpl::ConnectorImpl(shell::mojom::ConnectorPtr connector,
-                             const base::Closure& connection_error_closure)
+ConnectorImpl::ConnectorImpl(shell::mojom::ConnectorPtr connector)
     : connector_(std::move(connector)) {
-  connector_.set_connection_error_handler(connection_error_closure);
   thread_checker_.reset(new base::ThreadChecker);
 }
 ConnectorImpl::~ConnectorImpl() {}
 
 scoped_ptr<Connection> ConnectorImpl::Connect(const std::string& name) {
   ConnectParams params(name);
   return Connect(&params);
 }
 
 scoped_ptr<Connection> ConnectorImpl::Connect(ConnectParams* params) {
   // Bind this object to the current thread the first time it is used to
   // connect.
   if (!connector_.is_bound()) {
-    if (!unbound_state_.is_valid())
+    if (!unbound_state_.is_valid()) {
+      // It's possible to get here when the link to the shell has been severed
+      // (and so the connector pipe has been closed) but the app has chosen not
+      // to quit.
       return nullptr;
+    }
     connector_.Bind(std::move(unbound_state_));
     thread_checker_.reset(new base::ThreadChecker);
   }
   DCHECK(thread_checker_->CalledOnValidThread());
 
   DCHECK(params);
   std::string application_name = params->name();
   // We allow all interfaces on outgoing connections since we are presumably in
   // a position to know who we're talking to.
   // TODO(beng): We should filter outgoing interfaces also. The shell must pass
@@ skipping 20 matching lines @@
 }
 
 scoped_ptr<Connector> ConnectorImpl::Clone() {
   shell::mojom::ConnectorPtr connector;
   connector_->Clone(GetProxy(&connector));
   return make_scoped_ptr(
       new ConnectorImpl(connector.PassInterface()));
 }
 
 }  // namespace mojo