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/win32filesystem.h

@@ -1,64 +0,0 @@
-/*
- *  Copyright 2004 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_WIN32FILESYSTEM_H__
-#define _WEBRTC_BASE_WIN32FILESYSTEM_H__
-
-#include "fileutils.h"
-
-namespace rtc {
-
-class Win32Filesystem : public FilesystemInterface {
- public:
-  // This will attempt to delete the path located at filename.
-  // If the path points to a folder, it will fail with VERIFY
-  bool DeleteFile(const Pathname& filename) override;
-
-  // Creates a directory. This will call itself recursively to create /foo/bar even if
-  // /foo does not exist.
-  // Returns TRUE if function succeeds
-  bool CreateFolder(const Pathname& pathname) override;
-
-  // This moves a file from old_path to new_path. If the new path is on a 
-  // different volume than the old, it will attempt to copy and then delete
-  // the folder
-  // Returns true if the file is successfully moved
-  bool MoveFile(const Pathname& old_path, const Pathname& new_path) override;
-
-  // Returns true if a pathname is a directory
-  bool IsFolder(const Pathname& pathname) override;
-
-  // Returns true if a file exists at path
-  bool IsFile(const Pathname& path) override;
-
-  // Returns true if pathname refers to no filesystem object, every parent
-  // directory either exists, or is also absent.
-  bool IsAbsent(const Pathname& pathname) override;
-
-  // All of the following functions set pathname and return true if successful.
-  // Returned paths always include a trailing backslash.
-  // If create is true, the path will be recursively created.
-  // If append is non-null, it will be appended (and possibly created).
-
-  std::string TempFilename(const Pathname& dir,
-                           const std::string& prefix) override;
-
-  bool GetFileSize(const Pathname& path, size_t* size) override;
-
-  // A folder appropriate for storing temporary files (Contents are
-  // automatically deleted when the program exists)
-  bool GetTemporaryFolder(Pathname& path,
-                          bool create,
-                          const std::string* append) override;
-};
-
-}  // namespace rtc
-
-#endif  // WEBRTC_WINFILESYSTEM_H__