FileWrapper[Impl] modifications and actually remove the "Impl" class.

webrtc/modules/media_file/media_file_impl.cc

Index: webrtc/modules/media_file/media_file_impl.cc
diff --git a/webrtc/modules/media_file/media_file_impl.cc b/webrtc/modules/media_file/media_file_impl.cc
index 27fe9613a3ba8ab8833a2b0833946262303aebdb..9f9511d837ea6dfe424f38834628ee23e9be552e 100644
--- a/webrtc/modules/media_file/media_file_impl.cc
+++ b/webrtc/modules/media_file/media_file_impl.cc
@@ -371,12 +371,11 @@ int32_t MediaFileImpl::StartPlayingAudioFile(
         return -1;
     }
 
-    if(inputStream->OpenFile(fileName, true, loop) != 0)
-    {
-        delete inputStream;
-        WEBRTC_TRACE(kTraceError, kTraceFile, _id,
-                     "Could not open input file %s", fileName);
-        return -1;
+    if (!inputStream->OpenFile(fileName, true)) {
+      delete inputStream;
+      WEBRTC_TRACE(kTraceError, kTraceFile, _id, "Could not open input file %s",
+                   fileName);
+      return -1;
     }
 
     if(StartPlayingStream(*inputStream, loop, notificationTimeMs,
@@ -748,13 +747,11 @@ int32_t MediaFileImpl::StartRecordingAudioFile(
         return -1;
     }
 
-    if(outputStream->OpenFile(fileName, false) != 0)
-    {
-        delete outputStream;
-        WEBRTC_TRACE(kTraceError, kTraceFile, _id,
-                     "Could not open output file '%s' for writing!",
-                     fileName);
-        return -1;
+    if (!outputStream->OpenFile(fileName, false)) {
+      delete outputStream;
+      WEBRTC_TRACE(kTraceError, kTraceFile, _id,
+                   "Could not open output file '%s' for writing!", fileName);
+      return -1;
     }
 
     if(maxSizeBytes)