Move more utility functions to arc_util.

components/arc/arc_util.h

+// Copyright 2017 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.
+
+#ifndef COMPONENTS_ARC_ARC_UTIL_H_
+#define COMPONENTS_ARC_ARC_UTIL_H_
+

[Yusuke Sato, 2017/01/19 22:39:31]

I still feel we need a very lengthy document on how to use these utility
functions here (b/33667791). Can you add a TODO with that bug# if you agree?

[hidehiko, 2017/01/24 17:46:12]

Addressed in base CL.

+namespace arc {
+namespace util {
+
+// Returns true if ARC has been enabled through a commandline switch.

[Yusuke Sato, 2017/01/19 22:39:31]

Could you provide a bit more documents? What does "enabled through a command
line" actually mean to developers? How and when the command line switch is
typically set?

I know it's populated by session_manager based on CrOS' (libchromeos-ui
package's?) USE flag, and can be overridden by /etc/chorme_dev.conf, but I guess
it's unclear for most of ARC devs.

Also, when typically do we want to call the utility function?

[hidehiko, 2017/01/24 17:46:12]

Added more documentation in another CL.

As for detailed comments about relation to command line flags, let me work on it
in the CL to clean up the flags.

+bool IsArcEnabled();

[Yusuke Sato, 2017/01/19 22:39:31]

Name collision. ArcSessionManager has the same function but does a different
thing. Would it be possible to give better names to both? Currently "enabled"
has two different meaning.

[hidehiko, 2017/01/24 17:46:12]

Now, it should be resolved.

+
+// Returns true if ARC is available on the current board.

[Yusuke Sato, 2017/01/19 22:39:31]

When typically do we want to call the utility function? My understanding is that
except for a few rare occasions, developers should NOT call this at all.

[hidehiko, 2017/01/24 17:46:12]

Acknowledged.

+bool IsArcAvailable();
+
+// Returns true if ARC should run under Kiosk mode.
+bool IsArcKioskMode();
+
+// Checks if OptIn verification was disabled by switch in command line.

[Luis Héctor Chávez, 2017/01/19 18:09:15]

nit: s/OptIn/opt-in/

[Yusuke Sato, 2017/01/19 22:39:31]

Can you mention when typically this returns true? (like when
/etc/chrome_dev.conf is blah blah, maybe)

[hidehiko, 2017/01/24 17:46:12]

Done.

[hidehiko, 2017/01/24 17:46:12]

Hmmm, I guess rather than mentioning commandline flags about
/etc/chrome_dev.conf, the purpose looks important? WDYT?

+bool IsOptInVerificationDisabled();

[Luis Héctor Chávez, 2017/01/19 18:09:15]

nit: IsArcOptInVerificationDisabled()? That'll bring consistency with the rest
of the functions.

[hidehiko, 2017/01/24 17:46:12]

Done.

+

[Yusuke Sato, 2017/01/19 22:39:31]

Having 'void EnableArcForTesting()' (or a better name which is consistent with
L12) might be helpful to hide the command line switch from developers. At least
chrome/browser/sync/test/integration/sync_arc_package_helper.cc does the
following:

  base::CommandLine::ForCurrentProcess()->AppendSwitch(
      chromeos::switches::kEnableArc);

[hidehiko, 2017/01/24 17:46:12]

As written in another CL's TODO comment, let me work on this with cleaning up
flags.

[Yusuke Sato, 2017/01/24 20:36:58]

Eh.. where is the TODO? I think I'm lost..

+}  // namespace util
+}  // namespace arc
+
+#endif  // COMPONENTS_ARC_ARC_UTIL_H_