Extract kArcEnabled preference from ArcSessionManager part 2.

chrome/browser/chromeos/BUILD.gn

Index: chrome/browser/chromeos/BUILD.gn
diff --git a/chrome/browser/chromeos/BUILD.gn b/chrome/browser/chromeos/BUILD.gn
index e523896aca2caf1c6e9a8e345b0c05def6524f69..793adf438af30841a5679fe5a38cb3e467cdbf09 100644
--- a/chrome/browser/chromeos/BUILD.gn
+++ b/chrome/browser/chromeos/BUILD.gn
@@ -224,6 +224,8 @@ source_set("chromeos") {
     "arc/arc_auth_service.h",
     "arc/arc_optin_uma.cc",
     "arc/arc_optin_uma.h",
+    "arc/arc_play_store_enabled_preference_handler.cc",
+    "arc/arc_play_store_enabled_preference_handler.h",
     "arc/arc_service_launcher.cc",
     "arc/arc_service_launcher.h",
     "arc/arc_session_manager.cc",
@@ -1506,6 +1508,7 @@ source_set("unit_tests") {
     "accessibility/magnification_manager_unittest.cc",
     "accessibility/select_to_speak_event_handler_unittest.cc",
     "accessibility/spoken_feedback_event_rewriter_unittest.cc",
+    "arc/arc_play_store_enabled_preference_handler_unittest.cc",
     "arc/arc_session_manager_unittest.cc",
     "arc/arc_util_unittest.cc",
     "arc/downloads_watcher/arc_downloads_watcher_service_unittest.cc",