cros: Move TrayBluetoothHelper out of chrome into ash

ash/BUILD.gn

Index: ash/BUILD.gn
diff --git a/ash/BUILD.gn b/ash/BUILD.gn
index 8ffd929867704f1be529e5e33208ae7a90602d89..7b1de9d088e18db146a2b9f015312d29b13c4f53 100644
--- a/ash/BUILD.gn
+++ b/ash/BUILD.gn
@@ -205,6 +205,8 @@ component("ash") {
     "common/system/chromeos/bluetooth/bluetooth_observer.h",
     "common/system/chromeos/bluetooth/tray_bluetooth.cc",
     "common/system/chromeos/bluetooth/tray_bluetooth.h",
+    "common/system/chromeos/bluetooth/tray_bluetooth_helper.cc",
+    "common/system/chromeos/bluetooth/tray_bluetooth_helper.h",
     "common/system/chromeos/brightness/brightness_controller_chromeos.cc",
     "common/system/chromeos/brightness/brightness_controller_chromeos.h",
     "common/system/chromeos/brightness/tray_brightness.cc",
@@ -1166,6 +1168,7 @@ source_set("common_unittests") {
     "common/shelf/shelf_tooltip_manager_unittest.cc",
     "common/shelf/shelf_window_watcher_unittest.cc",
     "common/system/chromeos/audio/tray_audio_unittest.cc",
+    "common/system/chromeos/bluetooth/tray_bluetooth_helper_unittest.cc",
     "common/system/chromeos/brightness/tray_brightness_unittest.cc",
     "common/system/chromeos/ime_menu/ime_menu_tray_unittest.cc",
     "common/system/chromeos/media_security/multi_profile_media_tray_item_unittest.cc",
@@ -1275,6 +1278,7 @@ source_set("common_unittests") {
     "//chromeos",
     "//chromeos:power_manager_proto",
     "//chromeos:test_support_without_gmock",
+    "//device/bluetooth",
     "//services/ui/public/interfaces",
     "//testing/gmock",
     "//ui/accessibility",