Consolidate two IsArcWindow functions to reduce code duplication

components/arc/BUILD.gn

Index: components/arc/BUILD.gn
diff --git a/components/arc/BUILD.gn b/components/arc/BUILD.gn
index a78e3e625d6ddbc22c237fbd1c46da520f48522e..2dcd3894a146e0d0c3ef4261a22b32082be9925e 100644
--- a/components/arc/BUILD.gn
+++ b/components/arc/BUILD.gn
@@ -9,6 +9,8 @@ static_library("arc") {
   sources = [
     "arc_service_manager.cc",
     "arc_service_manager.h",
+    "arc_util.cc",
+    "arc_util.h",
     "audio/arc_audio_bridge.cc",
     "audio/arc_audio_bridge.h",
     "bluetooth/arc_bluetooth_bridge.cc",
@@ -68,6 +70,7 @@ static_library("arc") {
   deps = [
     "//ash:ash",
     "//ash/public/cpp:ash_public_cpp",
+    "//ash/shared:app_types",
     "//base",
     "//chromeos",
     "//chromeos:power_manager_proto",
@@ -110,8 +113,6 @@ static_library("arc_base") {
     "arc_session_runner.h",
     "arc_stop_reason.cc",
     "arc_stop_reason.h",
-    "arc_util.cc",
-    "arc_util.h",
     "instance_holder.h",
   ]
 
@@ -225,6 +226,7 @@ source_set("unit_tests") {
 
   deps = [
     ":arc_test_support",
+    "//ash/shared:app_types",
     "//base",
     "//base/test:test_support",
     "//chromeos",