Revert of Remove remains of webrtc/base (patchset #7 id:120001 of https://codereview.webrtc.org/297…

webrtc/base/flags.h

+/*
+ *  Copyright 2006 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+
+// Originally comes from shared/commandlineflags/flags.h
+
+// Flags are defined and declared using DEFINE_xxx and DECLARE_xxx macros,
+// where xxx is the flag type. Flags are referred to via FLAG_yyy,
+// where yyy is the flag name. For intialization and iteration of flags,
+// see the FlagList class. For full programmatic access to any
+// flag, see the Flag class.
+//
+// The implementation only relies and basic C++ functionality
+// and needs no special library or STL support.
+
+#ifndef WEBRTC_BASE_FLAGS_H_
+#define WEBRTC_BASE_FLAGS_H_
+
+
+// This header is deprecated and is just left here temporarily during
+// refactoring. See https://bugs.webrtc.org/7634 for more details.
+#include "webrtc/rtc_base/flags.h"
+
+#endif  // SHARED_COMMANDLINEFLAGS_FLAGS_H_