FileRecorder + FilePlayer: Let Create functions return unique_ptr

Because passing ownership in raw pointers makes kittens cry.

This also means we can ditch the Destroy functions and the protected
destructors. (Well, almost. We need to keep the old CreateFilePlayer
and DestroyFilePlayer around for a little while longer because of an
external caller.)

Review-Url: https://codereview.webrtc.org/2049683003
Cr-Commit-Position: refs/heads/master@{#13797}

webrtc/modules/utility/include/file_player.h

@@ -11,12 +11,15 @@
 #ifndef WEBRTC_MODULES_UTILITY_INCLUDE_FILE_PLAYER_H_
 #define WEBRTC_MODULES_UTILITY_INCLUDE_FILE_PLAYER_H_
 
+#include <memory>
+
 #include "webrtc/common_types.h"
 #include "webrtc/engine_configurations.h"
 #include "webrtc/modules/include/module_common_types.h"
 #include "webrtc/typedefs.h"
 
 namespace webrtc {
+
 class FileCallback;
 
 class FilePlayer {
@@ -26,11 +29,17 @@ class FilePlayer {
   enum { MAX_AUDIO_BUFFER_IN_BYTES = MAX_AUDIO_BUFFER_IN_SAMPLES * 2 };
 
   // Note: will return NULL for unsupported formats.
+  static std::unique_ptr<FilePlayer> NewFilePlayer(
+      const uint32_t instanceID,
+      const FileFormats fileFormat);
+
+  // Deprecated creation/destruction functions. Use NewFilePlayer instead.
   static FilePlayer* CreateFilePlayer(const uint32_t instanceID,
                                       const FileFormats fileFormat);
-
   static void DestroyFilePlayer(FilePlayer* player);
 
+  virtual ~FilePlayer() = default;
+
   // Read 10 ms of audio at |frequencyInHz| to |outBuffer|. |lengthInSamples|
   // will be set to the number of samples read (not the number of samples per
   // channel).
@@ -72,9 +81,6 @@ class FilePlayer {
 
   // Note: scaleFactor is in the range [0.0 - 2.0]
   virtual int32_t SetAudioScaling(float scaleFactor) = 0;
-
- protected:
-  virtual ~FilePlayer() {}
 };
 }  // namespace webrtc
 #endif  // WEBRTC_MODULES_UTILITY_INCLUDE_FILE_PLAYER_H_