Use mojo SystemTray interfaces for both mash and classic ash

chrome/browser/ui/ash/system_tray_delegate_chromeos.h

Index: chrome/browser/ui/ash/system_tray_delegate_chromeos.h
diff --git a/chrome/browser/ui/ash/system_tray_delegate_chromeos.h b/chrome/browser/ui/ash/system_tray_delegate_chromeos.h
index def75b50cec9e80b0584b0d608e1f397a4feed43..5d861ddb0c6a12ba30be0b9e1d8b1ff1a326f4ca 100644
--- a/chrome/browser/ui/ash/system_tray_delegate_chromeos.h
+++ b/chrome/browser/ui/ash/system_tray_delegate_chromeos.h
@@ -25,8 +25,6 @@
 #include "base/observer_list.h"
 #include "chrome/browser/chromeos/accessibility/accessibility_manager.h"
 #include "chrome/browser/chromeos/settings/shutdown_policy_handler.h"
-#include "chrome/browser/chromeos/system/system_clock.h"
-#include "chrome/browser/chromeos/system/system_clock_observer.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/supervised_user/supervised_user_service_observer.h"
 #include "chrome/browser/ui/browser_list_observer.h"
@@ -70,7 +68,6 @@ class SystemTrayDelegateChromeOS
       public user_manager::UserManager::UserSessionStateObserver,
       public SupervisedUserServiceObserver,
       public ShutdownPolicyHandler::Delegate,
-      public system::SystemClockObserver,
       public input_method::InputMethodManager::ImeMenuObserver {
  public:
   SystemTrayDelegateChromeOS();
@@ -92,10 +89,8 @@ class SystemTrayDelegateChromeOS
   bool IsUserSupervised() const override;
   bool IsUserChild() const override;
   void GetSystemUpdateInfo(ash::UpdateInfo* info) const override;
-  base::HourClockType GetHourClockType() const override;
   void ShowSettings() override;
   bool ShouldShowSettings() override;
-  void ShowDateSettings() override;
   void ShowSetTimeDialog() override;
   void ShowNetworkSettingsForGuid(const std::string& guid) override;
   void ShowDisplaySettings() override;
@@ -161,12 +156,6 @@ class SystemTrayDelegateChromeOS
 
   void UserChangedChildStatus(user_manager::User* user) override;
 
-  // browser tests need to call ShouldUse24HourClock().
-  bool GetShouldUse24HourClockForTesting() const;
-
-  // chromeos::system::SystemClockObserver implementation.
-  void OnSystemClockChanged(system::SystemClock*) override;
-
  private:
   ash::SystemTray* GetPrimarySystemTray();
 
@@ -176,8 +165,6 @@ class SystemTrayDelegateChromeOS
 
   bool UnsetProfile(Profile* profile);
 
-  bool ShouldUse24HourClock() const;
-
   void UpdateShowLogoutButtonInTray();
 
   void UpdateLogoutDialogDuration();
@@ -288,7 +275,6 @@ class SystemTrayDelegateChromeOS
   std::unique_ptr<PrefChangeRegistrar> local_state_registrar_;
   std::unique_ptr<PrefChangeRegistrar> user_pref_registrar_;
   Profile* user_profile_;
-  base::HourClockType clock_type_;
   int search_key_mapped_to_;
   bool screen_locked_;
   bool have_session_start_time_;