Make FileRotatingStream independent of StreamInterface

Bug: webrtc:7811
Change-Id: Ia5c07ad00e90d5b982750004eeb2c8e1cfbae4eb
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/212969
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#33579}

rtc_base/file_rotating_stream.h

@@ -27,13 +27,8 @@ namespace rtc {
 // constructor. It rotates the files once the current file is full. The
 // individual file size and the number of files used is configurable in the
 // constructor. Open() must be called before using this stream.
-class FileRotatingStream : public StreamInterface {
+class FileRotatingStream {
  public:
-  // Use this constructor for reading a directory previously written to with
-  // this stream.
-  FileRotatingStream(const std::string& dir_path,
-                     const std::string& file_prefix);
-
   // Use this constructor for writing to a directory. Files in the directory
   // matching the prefix will be deleted on open.
   FileRotatingStream(const std::string& dir_path,
@@ -41,20 +36,13 @@ class FileRotatingStream : public StreamInterface {
                      size_t max_file_size,
                      size_t num_files);
 
-  ~FileRotatingStream() override;
+  virtual ~FileRotatingStream();
 
-  // StreamInterface methods.
-  StreamState GetState() const override;
-  StreamResult Read(void* buffer,
-                    size_t buffer_len,
-                    size_t* read,
-                    int* error) override;
-  StreamResult Write(const void* data,
-                     size_t data_len,
-                     size_t* written,
-                     int* error) override;
-  bool Flush() override;
-  void Close() override;
+  bool IsOpen() const;
+
+  bool Write(const void* data, size_t data_len);
+  bool Flush();
+  void Close();
 
   // Opens the appropriate file(s). Call this before using the stream.
   bool Open();
@@ -63,6 +51,8 @@ class FileRotatingStream : public StreamInterface {
   // enabled by default for performance.
   bool DisableBuffering();
 
+  // Below two methods are public for testing only.
+
   // Returns the path used for the i-th newest file, where the 0th file is the
   // newest file. The file may or may not exist, this is just used for
   // formatting. Index must be less than GetNumFiles().
@@ -72,8 +62,6 @@ class FileRotatingStream : public StreamInterface {
   size_t GetNumFiles() const { return file_names_.size(); }
 
  protected:
-  size_t GetMaxFileSize() const { return max_file_size_; }
-
   void SetMaxFileSize(size_t size) { max_file_size_ = size; }
 
   size_t GetRotationIndex() const { return rotation_index_; }