FilePlayer: Remove unused default values for arguments

webrtc/modules/utility/include/file_player.h

Index: webrtc/modules/utility/include/file_player.h
diff --git a/webrtc/modules/utility/include/file_player.h b/webrtc/modules/utility/include/file_player.h
index 5f79fd28e21c5598d5ac835e164c305b65204e6b..508c2110a6b579f6f96adfed8bfec1ede52bbda9 100644
--- a/webrtc/modules/utility/include/file_player.h
+++ b/webrtc/modules/utility/include/file_player.h
@@ -57,16 +57,16 @@ class FilePlayer {
                                    uint32_t startPosition,
                                    float volumeScaling,
                                    uint32_t notification,
-                                   uint32_t stopPosition = 0,
-                                   const CodecInst* codecInst = NULL) = 0;
+                                   uint32_t stopPosition,
+                                   const CodecInst* codecInst) = 0;
 
   // Note: codecInst is used for pre-encoded files.
   virtual int32_t StartPlayingFile(InStream& sourceStream,
                                    uint32_t startPosition,
                                    float volumeScaling,
                                    uint32_t notification,
-                                   uint32_t stopPosition = 0,
-                                   const CodecInst* codecInst = NULL) = 0;
+                                   uint32_t stopPosition,
+                                   const CodecInst* codecInst) = 0;
 
   virtual int32_t StopPlayingFile() = 0;