Removes example code that isn't correctly wired up

mash/session/public/interfaces/session.mojom

Index: mash/session/public/interfaces/session.mojom
diff --git a/mash/session/public/interfaces/session.mojom b/mash/session/public/interfaces/session.mojom
deleted file mode 100644
index f81e98df04ed50f9420d05549919f9d6abceb709..0000000000000000000000000000000000000000
--- a/mash/session/public/interfaces/session.mojom
+++ /dev/null
@@ -1,19 +0,0 @@
-// Copyright 2016 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.
-
-module mash.session.mojom;
-
-interface ScreenlockStateListener {
-  // This method is called when the listener is initially added with the current
-  // lock state, and subsequently whenever the lock state changes.
-  ScreenlockStateChanged(bool locked);
-};
-
-interface Session {
-  Logout();
-  SwitchUser();
-  LockScreen();
-  UnlockScreen();
-  AddScreenlockStateListener(ScreenlockStateListener listener);
-};