Delete unused method FilesystemInterface::IsAbsent.

webrtc/rtc_base/unixfilesystem.h

 /*
  *  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.
  */
 
@@ skipping 28 matching lines @@
   // file or directory, which will be moved recursively.
   // Returns true if function succeeds.
   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 of pathname represents an existing file
   bool IsFile(const Pathname& pathname) 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;
-
   std::string TempFilename(const Pathname& dir,
                            const std::string& prefix) override;
 
   bool GetFileSize(const Pathname& path, size_t* size) override;
 
  private:
 #if defined(WEBRTC_ANDROID) || defined(WEBRTC_MAC)
   static char* provided_app_data_folder_;
   static char* provided_app_temp_folder_;
 #else
   static char* app_temp_path_;
 #endif
 
   static char* CopyString(const std::string& str);
 };
 
 }  // namespace rtc
 
 #endif  // WEBRTC_RTC_BASE_UNIXFILESYSTEM_H_