Use mojo SystemTray interfaces for both mash and classic ash

ash/BUILD.gn

Index: ash/BUILD.gn
diff --git a/ash/BUILD.gn b/ash/BUILD.gn
index d63fa1ec3164e45856e767ec7739d590c6570ec5..35725412407459c400e02c684facee2e6cbebe66 100644
--- a/ash/BUILD.gn
+++ b/ash/BUILD.gn
@@ -116,6 +116,8 @@ component("ash") {
     "common/metrics/pointer_metrics_recorder.cc",
     "common/metrics/pointer_metrics_recorder.h",
     "common/metrics/user_metrics_action.h",
+    "common/mojo_interface_factory.cc",
+    "common/mojo_interface_factory.h",
     "common/multi_profile_uma.cc",
     "common/multi_profile_uma.h",
     "common/palette_delegate.h",
@@ -357,6 +359,8 @@ component("ash") {
     "common/system/tray/system_tray.h",
     "common/system/tray/system_tray_bubble.cc",
     "common/system/tray/system_tray_bubble.h",
+    "common/system/tray/system_tray_controller.cc",
+    "common/system/tray/system_tray_controller.h",
     "common/system/tray/system_tray_delegate.cc",
     "common/system/tray/system_tray_delegate.h",
     "common/system/tray/system_tray_item.cc",
@@ -824,6 +828,7 @@ component("ash") {
   deps = [
     "//ash/autoclick/common:autoclick",
     "//ash/public/cpp",
+    "//ash/public/interfaces",
     "//ash/touch_hud",
     "//base",
     "//base:i18n",
@@ -836,6 +841,7 @@ component("ash") {
     "//components/wallpaper",
     "//media",
     "//net",
+    "//services/shell/public/cpp",
     "//skia",
     "//third_party/icu",
     "//ui/accessibility",