Migrate --enable-arc and --arc-available part 1.

components/arc/BUILD.gn

Index: components/arc/BUILD.gn
diff --git a/components/arc/BUILD.gn b/components/arc/BUILD.gn
index 64e834914f8e6d07967bb8d37cae0c4e01ad14a9..ccb7ba2c8dc8711878cf9a75e96cbc6165310f4d 100644
--- a/components/arc/BUILD.gn
+++ b/components/arc/BUILD.gn
@@ -108,6 +108,8 @@ static_library("arc_base") {
     "arc_session_observer.h",
     "arc_session_runner.cc",
     "arc_session_runner.h",
+    "arc_util.cc",
+    "arc_util.h",
     "instance_holder.h",
   ]
 
@@ -196,6 +198,7 @@ source_set("unit_tests") {
   sources = [
     "arc_service_manager_unittest.cc",
     "arc_session_runner_unittest.cc",
+    "arc_util_unittest.cc",
     "bluetooth/arc_bluetooth_bridge_unittest.cc",
     "bluetooth/bluetooth_struct_traits_unittest.cc",
     "bluetooth/bluetooth_type_converters_unittest.cc",
@@ -212,6 +215,7 @@ source_set("unit_tests") {
   deps = [
     ":arc_test_support",
     "//base",
+    "//base/test:test_support",
     "//chromeos",
     "//device/bluetooth",
     "//mojo/public/cpp/system:system",