Move view_types.h to view_type.h, since that's the standard name for enums.

content/public/common/view_types.h

-// Copyright (c) 2011 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 CONTENT_PUBLIC_COMMON_VIEW_TYPES_H_
-#define CONTENT_PUBLIC_COMMON_VIEW_TYPES_H_
-#pragma once
-
-namespace content {
-
-// Indicates different types of views.
-enum ViewTypeValues {
-  VIEW_TYPE_INVALID,
-  VIEW_TYPE_TAB_CONTENTS,
-  VIEW_TYPE_INTERSTITIAL_PAGE,
-  VIEW_TYPE_DEV_TOOLS_UI,
-
-  VIEW_TYPE_CONTENT_END
-};
-
-typedef int ViewType;
-
-}  // namespace content
-
-#endif  // CONTENT_PUBLIC_COMMON_VIEW_TYPES_H_