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

Will reland in two different commits to preserve git blame history.

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

Change-Id: I550da8525aeb9c5b8f96338fcf1c9714f3dcdab1
Reviewed-on: https://chromium-review.googlesource.com/554610
Reviewed-by: Henrik Kjellander <kjellander@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#18820}
diff --git a/webrtc/base/logsinks.h b/webrtc/base/logsinks.h
index 95e6dc6..e75120e 100644
--- a/webrtc/base/logsinks.h
+++ b/webrtc/base/logsinks.h
@@ -8,12 +8,61 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
-#ifndef WEBRTC_BASE_LOGSINKS_H_
-#define WEBRTC_BASE_LOGSINKS_H_
+#ifndef WEBRTC_BASE_FILE_ROTATING_LOG_SINK_H_
+#define WEBRTC_BASE_FILE_ROTATING_LOG_SINK_H_
 
+#include <memory>
+#include <string>
 
-// This header is deprecated and is just left here temporarily during
-// refactoring. See https://bugs.webrtc.org/7634 for more details.
-#include "webrtc/rtc_base/logsinks.h"
+#include "webrtc/base/constructormagic.h"
+#include "webrtc/base/filerotatingstream.h"
+#include "webrtc/base/logging.h"
 
-#endif  // WEBRTC_BASE_LOGSINKS_H_
+namespace rtc {
+
+// Log sink that uses a FileRotatingStream to write to disk.
+// Init() must be called before adding this sink.
+class FileRotatingLogSink : public LogSink {
+ public:
+  // |num_log_files| must be greater than 1 and |max_log_size| must be greater
+  // than 0.
+  FileRotatingLogSink(const std::string& log_dir_path,
+                      const std::string& log_prefix,
+                      size_t max_log_size,
+                      size_t num_log_files);
+  ~FileRotatingLogSink() override;
+
+  // Writes the message to the current file. It will spill over to the next
+  // file if needed.
+  void OnLogMessage(const std::string& message) override;
+
+  // Deletes any existing files in the directory and creates a new log file.
+  virtual bool Init();
+
+  // Disables buffering on the underlying stream.
+  bool DisableBuffering();
+
+ protected:
+  explicit FileRotatingLogSink(FileRotatingStream* stream);
+
+ private:
+  std::unique_ptr<FileRotatingStream> stream_;
+
+  RTC_DISALLOW_COPY_AND_ASSIGN(FileRotatingLogSink);
+};
+
+// Log sink that uses a CallSessionFileRotatingStream to write to disk.
+// Init() must be called before adding this sink.
+class CallSessionFileRotatingLogSink : public FileRotatingLogSink {
+ public:
+  CallSessionFileRotatingLogSink(const std::string& log_dir_path,
+                                 size_t max_total_log_size);
+  ~CallSessionFileRotatingLogSink() override;
+
+ private:
+  RTC_DISALLOW_COPY_AND_ASSIGN(CallSessionFileRotatingLogSink);
+};
+
+}  // namespace rtc
+
+#endif  // WEBRTC_BASE_FILE_ROTATING_LOG_SINK_H_