Remove unused files after SignedSettings is dead.

chrome/browser/chromeos/settings/mock_signed_settings_helper.cc

Index: chrome/browser/chromeos/settings/mock_signed_settings_helper.cc
diff --git a/chrome/browser/chromeos/settings/mock_signed_settings_helper.cc b/chrome/browser/chromeos/settings/mock_signed_settings_helper.cc
deleted file mode 100644
index 2386b6d0eaac32127fd9b0515da2328203af0de7..0000000000000000000000000000000000000000
--- a/chrome/browser/chromeos/settings/mock_signed_settings_helper.cc
+++ /dev/null
@@ -1,17 +0,0 @@
-// Copyright (c) 2012 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.
-
-#include "chrome/browser/chromeos/settings/mock_signed_settings_helper.h"
-
-#include "chrome/browser/policy/proto/device_management_backend.pb.h"
-
-namespace chromeos {
-
-MockSignedSettingsHelper::MockSignedSettingsHelper() {
-}
-
-MockSignedSettingsHelper::~MockSignedSettingsHelper() {
-}
-
-}  // namespace chromeos