[Extensions] Remove principalsPrivate API

chrome/common/extensions/api/principals_private.idl

Index: chrome/common/extensions/api/principals_private.idl
diff --git a/chrome/common/extensions/api/principals_private.idl b/chrome/common/extensions/api/principals_private.idl
deleted file mode 100644
index bc1925db8c377b06d46fe9e1ccc663efa70e5efe..0000000000000000000000000000000000000000
--- a/chrome/common/extensions/api/principals_private.idl
+++ /dev/null
@@ -1,18 +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.
-
-// Experimental APIs to trigger Chrome sign in actions.
-// Only enabled if the flag "new-profile-management" is set.
-namespace principalsPrivate {
-
-  interface Functions {
-    // Triggers Chrome sign out.
-    // Only enabled if the flag "new-profile-management" is set.
-    static void signOut();
-
-    // Shows the avatar bubble.
-    // Only enabled if the flag "new-profile-management" is set.
-    static void showAvatarBubble();
-  };
-};