Do nothing on OnSessionStopped if ARC is being restarted.

components/arc/arc_session_runner.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_session_runner.h"
 
 #include "base/logging.h"
 #include "base/memory/ref_counted.h"
 #include "base/task_runner.h"
 #include "components/arc/arc_session.h"
@@ skipping 138 matching lines @@
   DCHECK(arc_session_);
   DCHECK(!restart_timer_.IsRunning());
 
   VLOG(0) << "ARC ready";
   state_ = State::RUNNING;
 
   for (auto& observer : observer_list_)
     observer.OnSessionReady();
 }
 
-void ArcSessionRunner::OnSessionStopped(StopReason stop_reason) {
+void ArcSessionRunner::OnSessionStopped(StopReason stop_reason,
+                                        bool restarting) {
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK_NE(state_, State::STOPPED);
   DCHECK(arc_session_);
   DCHECK(!restart_timer_.IsRunning());
+  // Because ArcSession won't restart automatically by itself, |restarting|

[Yusuke Sato, 2017/02/28 21:07:17]

Then you can remove L165-167 :)

[hidehiko, 2017/03/01 09:10:05]

Done.

+  // should be always false.
+  DCHECK(!restarting);
 
   VLOG(0) << "ARC stopped: " << stop_reason;
   arc_session_->RemoveObserver(this);
   arc_session_.reset();
 
   // If RUNNING, ARC instance unexpectedly crashed so we need to restart it
   // automatically.
   // If STOPPING, at least once RequestStop() is called. If |session_started_|
   // is true, RequestStart() is following so schedule to restart ARC session.
   // Otherwise, do nothing.
   // If STARTING, ARC instance has not been booted properly, so do not
   // restart it automatically.
   if (state_ == State::RUNNING ||
       (state_ == State::STOPPING && run_requested_)) {
     // This check is for RUNNING case. In RUNNING case |run_requested_| should
     // be always true, because if once RequestStop() is called, the state_
     // will be set to STOPPING.
     DCHECK(run_requested_);
 
     // There was a previous invocation and it crashed for some reason. Try
     // starting ARC instance later again.
     // Note that even |restart_delay_| is 0 (for testing), it needs to
     // PostTask, because observer callback may call RequestStart()/Stop().
     VLOG(0) << "ARC restarting";
     restart_timer_.Start(FROM_HERE, restart_delay_,
                          base::Bind(&ArcSessionRunner::StartArcSession,
                                     weak_ptr_factory_.GetWeakPtr()));
+    restarting = true;  // Overwrite the passing argument to true.

[hidehiko, 2017/02/28 16:33:48]

Note: another approach will be; not calling OnSessionStopped on restarting.
However, at the moment it makes testing difficult, so I kept it.

   }
 
-  // TODO(hidehiko): Consider to let observers know whether there is scheduled
-  // restarting event, or not.
   state_ = State::STOPPED;
   for (auto& observer : observer_list_)
-    observer.OnSessionStopped(stop_reason);
+    observer.OnSessionStopped(stop_reason, restarting);
 }
 
 }  // namespace arc