arc: kArcCompatibleFilesystemChosen pref to local state and integer.

chrome/browser/chromeos/arc/arc_util.h

Index: chrome/browser/chromeos/arc/arc_util.h
diff --git a/chrome/browser/chromeos/arc/arc_util.h b/chrome/browser/chromeos/arc/arc_util.h
index 7765832e9abad9327bef3b6adbac810e0718fc6c..80b8a9faa16b46519e0ec3406c1d21278e8ab8c8 100644
--- a/chrome/browser/chromeos/arc/arc_util.h
+++ b/chrome/browser/chromeos/arc/arc_util.h
@@ -5,12 +5,17 @@
 #ifndef CHROME_BROWSER_CHROMEOS_ARC_ARC_UTIL_H_
 #define CHROME_BROWSER_CHROMEOS_ARC_ARC_UTIL_H_
 
+#include <stdint.h>
+
+#include "base/callback_forward.h"
+
 // Most utility should be put in components/arc/arc_util.{h,cc}, rather than
 // here. However, some utility implementation requires other modules defined in
 // chrome/, so this file contains such utilities.
 // Note that it is not allowed to have dependency from components/ to chrome/
 // by DEPS.
 
+class AccountId;
 class Profile;
 
 namespace base {
@@ -19,6 +24,22 @@ class FilePath;
 
 namespace arc {
 
+// Values to be stored in the local state preference to keep track of the
+// filesystem encryption migration status.
+enum FileSystemCompatibilityState : int32_t {
+  // No migiration has happend, user keeps using the old file system.
+  kFileSystemIncompatible = 0,

[Junichi Uekawa, 2017/05/11 22:15:34]

what about the case that the ext4 crypto is already in use when user has created
the directory in cryptohome?

New users always get ext4 crypto file system on dircrypto capable systems now.

They get notifications ?

+  // Migration has happend. New filesystem is in use.
+  kFileSystemCompatible = 1,
+  // Migration has happend, and a notification about the fact was already shown.
+  // TODO(kinaba): This value isn't yet used until crbug.com/711095 is done.
+  kFileSystemCompatibleAndNotified = 2,
+
+  // Existing code assumes that kFileSystemIncompatible is the only state
+  // representing incompatibility and other values are all variants of
+  // "compatible" state. Be careful in the case adding a new enum value.
+};
+
 // Returns true if ARC is allowed to run for the given profile.
 // Otherwise, returns false, e.g. if the Profile is not for the primary user,
 // ARC is not available on the device, it is in the flow to set up managed
@@ -78,9 +99,13 @@ void SetArcPlayStoreEnabledForProfile(Profile* profile, bool enabled);
 // ArcBackupRestoreEnabled and ArcLocationServiceEnabled) are managed.
 bool AreArcAllOptInPreferencesManagedForProfile(const Profile* profile);
 
-// Returns whether ARC can run on the filesystem mounted at |path|.
-// This function should run only on threads where IO operations are allowed.
-bool IsArcCompatibleFilesystem(const base::FilePath& path);
+// 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);
 
 }  // namespace arc