Fix ArcBridgeBootstrap race issues.

components/arc/arc_bridge_service_impl.cc

 // Copyright 2015 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 "components/arc/arc_bridge_service_impl.h"
 
 #include <string>
 #include <utility>
 
 #include "base/command_line.h"
 #include "base/json/json_writer.h"
 #include "base/message_loop/message_loop.h"
 #include "base/sequenced_task_runner.h"
 #include "base/sys_info.h"
 #include "base/task_runner_util.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/time/time.h"
 #include "chromeos/chromeos_switches.h"
 #include "chromeos/dbus/dbus_method_call_status.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
-#include "chromeos/dbus/session_manager_client.h"
 #include "components/arc/arc_bridge_host_impl.h"
 #include "components/prefs/pref_registry_simple.h"
 #include "components/prefs/pref_service.h"
 
 namespace arc {
 
 extern ArcBridgeService* g_arc_bridge_service;
 
 namespace {
 constexpr int64_t kReconnectDelayInSeconds = 5;
 }  // namespace
 
-ArcBridgeServiceImpl::ArcBridgeServiceImpl(
-    std::unique_ptr<ArcBridgeBootstrap> bootstrap)
-    : bootstrap_(std::move(bootstrap)),
-      session_started_(false),
+ArcBridgeServiceImpl::ArcBridgeServiceImpl()
+    : session_started_(false),
+      factory_(base::Bind(ArcBridgeBootstrap::Create)),
       weak_factory_(this) {
   DCHECK(!g_arc_bridge_service);
   g_arc_bridge_service = this;
-  bootstrap_->set_delegate(this);
 }
 
 ArcBridgeServiceImpl::~ArcBridgeServiceImpl() {
   DCHECK(g_arc_bridge_service == this);
   g_arc_bridge_service = nullptr;
 }
 
 void ArcBridgeServiceImpl::HandleStartup() {
   DCHECK(CalledOnValidThread());
   if (session_started_)
@@ skipping 19 matching lines @@
 void ArcBridgeServiceImpl::PrerequisitesChanged() {
   DCHECK(CalledOnValidThread());
   VLOG(1) << "Prerequisites changed. "
           << "state=" << static_cast<uint32_t>(state())
           << ", session_started=" << session_started_;
   if (state() == State::STOPPED) {
     if (!session_started_)
       return;
     VLOG(0) << "Prerequisites met, starting ARC";
     SetStopReason(StopReason::SHUTDOWN);
+
     SetState(State::CONNECTING);
+    bootstrap_ = factory_.Run();
+    bootstrap_->set_delegate(this);
     bootstrap_->Start();
   } else {
     if (session_started_)
       return;
     VLOG(0) << "Prerequisites stopped being met, stopping ARC";
     StopInstance();
   }
 }
 
 void ArcBridgeServiceImpl::StopInstance() {
   DCHECK(CalledOnValidThread());
   if (state() == State::STOPPED || state() == State::STOPPING) {
     VLOG(1) << "StopInstance() called when ARC is not running";
     return;
   }
 
+  // We were explicitly asked to stop, so do not reconnect.
+  reconnect_ = false;
+
   VLOG(1) << "Stopping ARC";
+  DCHECK(bootstrap_.get());
   SetState(State::STOPPING);
   arc_bridge_host_.reset();
+
+  // Note: this can call OnStopped() internally as a callback.
   bootstrap_->Stop();
-
-  // We were explicitly asked to stop, so do not reconnect.
-  reconnect_ = false;
 }
 
 void ArcBridgeServiceImpl::OnConnectionEstablished(
     mojom::ArcBridgeInstancePtr instance) {
   DCHECK(CalledOnValidThread());
   if (state() != State::CONNECTING) {
     VLOG(1) << "StopInstance() called while connecting";
     return;
   }
 
   arc_bridge_host_.reset(new ArcBridgeHostImpl(std::move(instance)));
 
   // The container can be considered to have been successfully launched, so
   // restart if the connection goes down without being requested.
   reconnect_ = true;
   VLOG(0) << "ARC ready";
   SetState(State::READY);
 }
 
 void ArcBridgeServiceImpl::OnStopped(StopReason stop_reason) {
   DCHECK(CalledOnValidThread());
+  VLOG(0) << "ARC stopped: " << static_cast<int>(stop_reason);

[Luis Héctor Chávez, 2016/09/15 23:08:49]

Can we have an operator<< for StopReason? That'll make the logs easier to read
without having to correlate what version was being run.

[hidehiko, 2016/09/20 13:35:19]

Done.

   arc_bridge_host_.reset();
+  bootstrap_.reset();
   SetStopReason(stop_reason);
   SetState(State::STOPPED);
-  VLOG(0) << "ARC stopped";
 
   if (reconnect_) {
     // There was a previous invocation and it crashed for some reason. Try
     // starting the container again.
     reconnect_ = false;
     VLOG(0) << "ARC reconnecting";
     if (use_delay_before_reconnecting_) {
       // Instead of immediately trying to restart the container, give it some
       // time to finish tearing down in case it is still in the process of
       // stopping.
       base::MessageLoop::current()->task_runner()->PostDelayedTask(
           FROM_HERE, base::Bind(&ArcBridgeServiceImpl::PrerequisitesChanged,
                                 weak_factory_.GetWeakPtr()),
           base::TimeDelta::FromSeconds(kReconnectDelayInSeconds));
     } else {
       // Restart immediately.
       PrerequisitesChanged();
     }
   }
 }
 
 }  // namespace arc