chromeos: Refactor ash SystemTrayDelegate enterprise methods to mojo

ash/system/user/user_card_view.cc

Index: ash/system/user/user_card_view.cc
diff --git a/ash/system/user/user_card_view.cc b/ash/system/user/user_card_view.cc
index 93034cbf5b2ff3ad2a1720cbd41e66a486f6383a..b518a9d83b64c8dd04f12f6ab1a4598c606ec3d3 100644
--- a/ash/system/user/user_card_view.cc
+++ b/ash/system/user/user_card_view.cc
@@ -16,7 +16,6 @@
 #include "ash/shell.h"
 #include "ash/strings/grit/ash_strings.h"
 #include "ash/system/tray/system_tray_controller.h"
-#include "ash/system/tray/system_tray_delegate.h"
 #include "ash/system/tray/tray_constants.h"
 #include "ash/system/tray/tray_popup_item_style.h"
 #include "ash/system/user/rounded_image_view.h"
@@ -125,7 +124,7 @@ PublicAccountUserDetails::PublicAccountUserDetails() : learn_more_(nullptr) {
   display_name = kDisplayNameMark[0] + display_name + kDisplayNameMark[0];
   // Retrieve the domain managing the device and wrap it with markers.
   base::string16 domain = base::UTF8ToUTF16(
-      Shell::Get()->system_tray_delegate()->GetEnterpriseDomain());
+      Shell::Get()->system_tray_controller()->enterprise_domain());
   base::RemoveChars(domain, kDisplayNameMark, &domain);
   base::i18n::WrapStringWithLTRFormatting(&domain);
   // Retrieve the label text, inserting the display name and domain.