arc-bridge: Enable ARC with a command-line flag

components/BUILD.gn

Index: components/BUILD.gn
diff --git a/components/BUILD.gn b/components/BUILD.gn
index b24ef8e89a7e5855eb5a25844c7d425c5ed2b408..37b2507cb230fea105ffcdb48725cefd8b4f1293 100644
--- a/components/BUILD.gn
+++ b/components/BUILD.gn
@@ -91,6 +91,7 @@ group("all_components") {
     deps += [
       "//components/about_handler",
       "//components/app_modal",
+      "//components/arc",
       "//components/auto_login_parser",
       "//components/autofill/content/browser",
       "//components/autofill/content/common",
@@ -224,15 +225,12 @@ group("all_components") {
 
     if (!is_chromeos) {
       deps -= [
+        "//components/arc",
         "//components/pairing",
         "//components/wifi_sync",
       ]
     }
 
-    if (is_chromeos && enable_arc) {
-      deps += [ "//components/arc" ]
-    }
-
     if (!use_ash) {
       deps -= [ "//components/exo" ]
     }
@@ -510,10 +508,10 @@ test("components_unittests") {
       }
     }
     if (is_chromeos) {
-      deps += [ "//components/ownership:unit_tests" ]
-    }
-    if (is_chromeos && enable_arc) {
-      deps += [ "//components/arc:unit_tests" ]
+      deps += [
+        "//components/arc:unit_tests",
+        "//components/ownership:unit_tests",
+      ]
     }
 
     # TODO(GYP) need this target.