Policy implementation for encryptfs to ext4 migration strategy

chrome/browser/chromeos/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 CHROME_BROWSER_CHROMEOS_ARC_ARC_UTIL_H_
 #define CHROME_BROWSER_CHROMEOS_ARC_ARC_UTIL_H_
 
 #include <stdint.h>
 
 #include "base/callback_forward.h"
@@ skipping 94 matching lines @@
 bool AreArcAllOptInPreferencesManagedForProfile(const Profile* profile);
 
 // Checks and updates the preference value whether the underlying filesystem
 // for the profile is compatible with ARC, when necessary. After it's done (or
 // skipped), |callback| is run either synchronously or asynchronously.
 void UpdateArcFileSystemCompatibilityPrefIfNeeded(
     const AccountId& account_id,
     const base::FilePath& profile_path,
     const base::Closure& callback);
 
+// Returns if the migration from ecryptfs to ext4 is allowed. It is true if the
+// flag specifying the need to check the policy is missing or if the device is

[bartfab (slow), 2017/06/12 12:49:04]

"the flag specifying the need to check the policy" - Which flag? Which policy?
Assume that the reader of this comment has no context.

[igorcov, 2017/06/12 16:50:09]

Done.

+// consumer owned or if the device policy is present and has the value
+// |kAllowMigration|. The response is cached the first time the function is
+// used, and the policy update won't change the return value after that.

[bartfab (slow), 2017/06/12 12:49:04]

1: Nit: s/the/a/
2: Nit: s/after that/after that until the next Chrome restart/
3: If Chrome crashes, comes back up again and the policy has changed, will that
cause problems?

[igorcov, 2017/06/12 16:50:10]

1,2: Done
3: After Chrome crash, user has to sign in and the session starts as if after
the boot. I think it would be the same flow.

[bartfab (slow), 2017/06/13 09:56:01]

Re 3: Actually, no. login_manager is a watchdog that catches Chrome crashes and
restarts the browser, without requiring you to log in again.

[igorcov, 2017/06/16 11:13:03]

Changed the code so that policy is decoded every time we set the value. The
reason is, in previous version the policy though decoded was not propagated
in local state after the crash, so ARC became disabled for every enrolled
device.

Current functionality makes ARC disabled after crash if policy was changed
from migration allowed to disabled, and in other case the user is notified
that sign out + sign in is required for a critical update. This functionality
looks good to me. Thank you.

+bool IsArcMigrationAllowed();
+
+// For testing IsArcMigrationAllowed, the global flags have to be reset before
+// every test.
+void ResetArcMigrationAllowedForTesting();
+
 }  // namespace arc
 
 #endif  // CHROME_BROWSER_CHROMEOS_ARC_ARC_UTIL_H_