Reland "Move webrtc/{base => rtc_base}" (https://codereview.webrtc.org/2877023002)

Reland the base->rtc_base without adding stub headers (will be
done in follow-up CL). This preserves git blame history of all files.

BUG=webrtc:7634
NOTRY=True
TBR=kwiberg@webrtc.org

Change-Id: Iea3bb6f3f67b8374c96337b63e8f5aa3e6181012
Reviewed-on: https://chromium-review.googlesource.com/554611
Reviewed-by: Henrik Kjellander <kjellander@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#18821}

webrtc/base/macutils.h

@@ -1,50 +0,0 @@
-/*
- *  Copyright 2007 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.
- */
-
-#ifndef WEBRTC_BASE_MACUTILS_H__
-#define WEBRTC_BASE_MACUTILS_H__
-
-#include <CoreFoundation/CoreFoundation.h>
-#include <string>
-
-namespace rtc {
-
-///////////////////////////////////////////////////////////////////////////////
-
-// Note that some of these functions work for both iOS and Mac OS X.  The ones
-// that are specific to Mac are #ifdef'ed as such.
-
-bool ToUtf8(const CFStringRef str16, std::string* str8);
-bool ToUtf16(const std::string& str8, CFStringRef* str16);
-
-#if defined(WEBRTC_MAC) && !defined(WEBRTC_IOS)
-void DecodeFourChar(UInt32 fc, std::string* out);
-
-enum MacOSVersionName {
-  kMacOSUnknown,       // ???
-  kMacOSOlder,         // 10.2-
-  kMacOSPanther,       // 10.3
-  kMacOSTiger,         // 10.4
-  kMacOSLeopard,       // 10.5
-  kMacOSSnowLeopard,   // 10.6
-  kMacOSLion,          // 10.7
-  kMacOSMountainLion,  // 10.8
-  kMacOSMavericks,     // 10.9
-  kMacOSNewer,         // 10.10+
-};
-
-MacOSVersionName GetOSVersionName();
-#endif
-
-///////////////////////////////////////////////////////////////////////////////
-
-}  // namespace rtc
-
-#endif  // WEBRTC_BASE_MACUTILS_H__