Enable ArcAvailableForChildAccount by default.

Leave the flag in place so we can revert the state in case we have any blockers.

R=escordeiro@chromium.org, yusukes@chromium.org

Bug: 828983
Change-Id: I9886bde062fc076acc34fe14cf42203784ef18f5
Reviewed-on: https://chromium-review.googlesource.com/1089150
Commit-Queue: B. Menegola <menegola@chromium.org>
Reviewed-by: Yusuke Sato <yusukes@chromium.org>
Reviewed-by: Yury Khmel <khmel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#565029}

components/arc/arc_features.cc

@@ -8,7 +8,7 @@ namespace arc {
 
 // Controls whether ARC is available for CHILD accounts.
 const base::Feature kAvailableForChildAccountFeature{
-    "ArcAvailableForChildAccount", base::FEATURE_DISABLED_BY_DEFAULT};
+    "ArcAvailableForChildAccount", base::FEATURE_ENABLED_BY_DEFAULT};
 
 // Controls ACTION_BOOT_COMPLETED broadcast for third party applications on ARC.
 // When disabled, third party apps will not receive this broadcast.

components/arc/arc_util_unittest.cc

@@ -198,7 +198,7 @@ TEST_F(ArcUtilTest, IsArcAllowedForUser) {
       {user_manager::USER_TYPE_PUBLIC_ACCOUNT, true},
       {user_manager::USER_TYPE_SUPERVISED, false},
       {user_manager::USER_TYPE_KIOSK_APP, false},
-      {user_manager::USER_TYPE_CHILD, false},
+      {user_manager::USER_TYPE_CHILD, true},
       {user_manager::USER_TYPE_ARC_KIOSK_APP, true},
       {user_manager::USER_TYPE_ACTIVE_DIRECTORY, true},
   };