Add unit test for ArcBluetoothBridge and TypeConverter

components/arc/BUILD.gn

Index: components/arc/BUILD.gn
diff --git a/components/arc/BUILD.gn b/components/arc/BUILD.gn
index 836576ba32f300c065b2c000122a7dc31d766539..fc112414ab372a6d919c3c36b142a7d15e817d21 100644
--- a/components/arc/BUILD.gn
+++ b/components/arc/BUILD.gn
@@ -142,6 +142,8 @@ static_library("arc_test_support") {
     "test/fake_arc_bridge_instance.h",
     "test/fake_arc_bridge_service.cc",
     "test/fake_arc_bridge_service.h",
+    "test/fake_bluetooth_instance.cc",
+    "test/fake_bluetooth_instance.h",
     "test/fake_notifications_instance.cc",
     "test/fake_notifications_instance.h",
     "test/fake_policy_instance.cc",
@@ -160,6 +162,8 @@ source_set("unit_tests") {
   testonly = true
   sources = [
     "arc_bridge_service_unittest.cc",
+    "bluetooth/arc_bluetooth_bridge_unittest.cc",
+    "bluetooth/bluetooth_type_converters_unittest.cc",
     "ime/arc_ime_service_unittest.cc",
     "intent_helper/activity_icon_loader_unittest.cc",
     "intent_helper/arc_intent_helper_bridge_unittest.cc",
@@ -175,6 +179,7 @@ source_set("unit_tests") {
     "//chromeos",
     "//ipc/mojo:mojo",
     "//mojo/public/cpp/system:system",
+    "//testing/gmock",
     "//testing/gtest",
     "//ui/aura",
     "//ui/base:test_support",