ARC is not allowed for incognito profile.

chrome/browser/chromeos/arc/arc_session_manager.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 "chrome/browser/chromeos/arc/arc_session_manager.h"
 
 #include <utility>
 
 #include "ash/common/shelf/shelf_delegate.h"
 #include "ash/common/wm_shell.h"
@@ skipping 145 matching lines @@
   if (!profile) {
     VLOG(1) << "ARC is not supported for systems without profile.";
     return false;
   }
 
   if (!chromeos::ProfileHelper::IsPrimaryProfile(profile)) {
     VLOG(1) << "Non-primary users are not supported in ARC.";
     return false;
   }
 
+  // IsPrimaryProfile can return true for an incognito profile corresponding

[hidehiko, 2017/01/11 14:29:42]

Note: I'm not very sure if this is intentional behavior or not, but
IsPrimaryProfile() is used in non-ARC code as well, so considering the
side-effect, I'd like to fix this in ARC code for now.

I think, maybe we should talk to Profile experts and other clients
(wallpaper/vpn) team later?

+  // to the primary profile, but ARC does not support it.
+  if (profile->IsOffTheRecord()) {
+    VLOG(1) << "Incognito profile is not supported in ARC.";
+    return false;
+  }
+
   if (profile->IsLegacySupervised()) {
     VLOG(1) << "Supervised users are not supported in ARC.";
     return false;
   }
 
   user_manager::User const* const user =
       chromeos::ProfileHelper::Get()->GetUserByProfile(profile);
   if ((!user || !user->HasGaiaAccount()) && !IsArcKioskMode()) {
     VLOG(1) << "Users without GAIA accounts are not supported in ARC.";
     return false;
@@ skipping 823 matching lines @@
       return os << "ACTIVE";
   }
 
   // Some compiler reports an error even if all values of an enum-class are
   // covered indivisually in a switch statement.
   NOTREACHED();
   return os;
 }
 
 }  // namespace arc