mash: Migrate remaining tray observers and notify functions.

ash/system/chromeos/screen_security/screen_share_observer.h

Index: ash/system/chromeos/screen_security/screen_share_observer.h
diff --git a/ash/system/chromeos/screen_security/screen_share_observer.h b/ash/system/chromeos/screen_security/screen_share_observer.h
deleted file mode 100644
index fb6a556fa2cd4c05218ea01a7b062c447b4f5fad..0000000000000000000000000000000000000000
--- a/ash/system/chromeos/screen_security/screen_share_observer.h
+++ /dev/null
@@ -1,29 +0,0 @@
-// Copyright 2013 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef ASH_SYSTEM_CHROMEOS_SCREEN_SHARE_SCREEN_SHARE_OBSERVER_H_
-#define ASH_SYSTEM_CHROMEOS_SCREEN_SHARE_SCREEN_SHARE_OBSERVER_H_
-
-#include "base/callback.h"
-#include "base/strings/string16.h"
-
-namespace ash {
-
-class ScreenShareObserver {
- public:
-  // Called when screen share is started.
-  virtual void OnScreenShareStart(
-      const base::Closure& stop_callback,
-      const base::string16& helper_name) = 0;
-
-  // Called when screen share is stopped.
-  virtual void OnScreenShareStop() = 0;
-
- protected:
-  virtual ~ScreenShareObserver() {}
-};
-
-}  // namespace ash
-
-#endif  // ASH_SYSTEM_CHROMEOS_SCREEN_SHARE_SCREEN_SHARE_OBSERVER_H_