Delete unused method FilesystemInterface::DeleteEmptyFolder.

It's left-over since cl https://codereview.webrtc.org/2887093002.

In addition, fix override declarations and formatting in
win32filesystem.h.

BUG=webrtc:7345,webrtc:6424

Review-Url: https://codereview.webrtc.org/2930023002
Cr-Commit-Position: refs/heads/master@{#18549}

webrtc/base/fileutils.h

@@ -85,12 +85,6 @@ class FilesystemInterface {
   // non-existent file.
   virtual bool DeleteFile(const Pathname &filename) = 0;
 
-  // This will attempt to delete the empty folder located at 'folder'
-  // It DCHECKs and returns false if the path points to a file or a non-existent
-  // folder. It fails normally if the folder is not empty or can otherwise
-  // not be deleted.
-  virtual bool DeleteEmptyFolder(const Pathname &folder) = 0;
-
   // Creates a directory. This will call itself recursively to create /foo/bar
   // even if /foo does not exist. Returns true if the function succeeds.
   virtual bool CreateFolder(const Pathname &pathname) = 0;

webrtc/base/unixfilesystem.cc

@@ -133,17 +133,6 @@ bool UnixFilesystem::DeleteFile(const Pathname &filename) {
   return ::unlink(filename.pathname().c_str()) == 0;
 }
 
-bool UnixFilesystem::DeleteEmptyFolder(const Pathname &folder) {
-  LOG(LS_INFO) << "Deleting folder" << folder.pathname();
-
-  if (!IsFolder(folder)) {
-    RTC_DCHECK(IsFolder(folder));
-    return false;
-  }
-  std::string no_slash(folder.pathname(), 0, folder.pathname().length()-1);
-  return ::rmdir(no_slash.c_str()) == 0;
-}
-
 bool UnixFilesystem::GetTemporaryFolder(Pathname &pathname, bool create,
                                         const std::string *append) {
 #if defined(WEBRTC_ANDROID) || defined(WEBRTC_MAC)

webrtc/base/unixfilesystem.h

@@ -38,11 +38,6 @@ class UnixFilesystem : public FilesystemInterface {
   // It will fail with VERIY if you pass it a non-existant file, or a directory.
   bool DeleteFile(const Pathname& filename) override;
 
-  // This will attempt to delete the folder located at 'folder'
-  // It DCHECKs and returns false if you pass it a non-existant folder or a
-  // plain file.
-  bool DeleteEmptyFolder(const Pathname& folder) override;
-
   // Creates a directory. This will call itself recursively to create /foo/bar
   // even if /foo does not exist. All created directories are created with the
   // given mode.

webrtc/base/win32filesystem.cc

@@ -72,13 +72,6 @@ bool Win32Filesystem::DeleteFile(const Pathname &filename) {
   return ::DeleteFile(ToUtf16(filename.pathname()).c_str()) != 0;
 }
 
-bool Win32Filesystem::DeleteEmptyFolder(const Pathname &folder) {
-  LOG(LS_INFO) << "Deleting folder " << folder.pathname();
-
-  std::string no_slash(folder.pathname(), 0, folder.pathname().length()-1);
-  return ::RemoveDirectory(ToUtf16(no_slash).c_str()) != 0;
-}
-
 bool Win32Filesystem::GetTemporaryFolder(Pathname &pathname, bool create,
                                          const std::string *append) {
   wchar_t buffer[MAX_PATH + 1];

webrtc/base/win32filesystem.h

@@ -19,48 +19,47 @@ 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
-  virtual bool DeleteFile(const Pathname &filename);
-
-  // This will attempt to delete an empty folder. If the path does not point to
-  // a folder, it fails with VERIFY. If the folder is not empty, it fails normally
-  virtual bool DeleteEmptyFolder(const Pathname &folder);
+  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
-  virtual bool CreateFolder(const Pathname &pathname);
-  
+  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
-  virtual bool MoveFile(const Pathname &old_path, const Pathname &new_path);
-  
+  bool MoveFile(const Pathname& old_path, const Pathname& new_path) override;
+
   // Returns true if a pathname is a directory
-  virtual bool IsFolder(const Pathname& pathname);
-  
+  bool IsFolder(const Pathname& pathname) override;
+
   // Returns true if a file exists at path
-  virtual bool IsFile(const Pathname &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.
-  virtual bool IsAbsent(const Pathname& pathname);
+  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).
 
-  virtual std::string TempFilename(const Pathname &dir, const std::string &prefix);
+  std::string TempFilename(const Pathname& dir,
+                           const std::string& prefix) override;
 
-  virtual bool GetFileSize(const Pathname& path, size_t* size);
-  virtual bool GetFileTime(const Pathname& path, FileTimeType which,
-                           time_t* time);
+  bool GetFileSize(const Pathname& path, size_t* size) override;
+  bool GetFileTime(const Pathname& path,
+                   FileTimeType which,
+                   time_t* time) override;
 
   // A folder appropriate for storing temporary files (Contents are
   // automatically deleted when the program exists)
-  virtual bool GetTemporaryFolder(Pathname &path, bool create,
-                                 const std::string *append);
+  bool GetTemporaryFolder(Pathname& path,
+                          bool create,
+                          const std::string* append) override;
 
  private:
   // Returns the path to the running application.