Revert of Remove ignored return code from modules.

webrtc/modules/media_file/media_file_impl.cc

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 77 matching lines @@
 int64_t MediaFileImpl::TimeUntilNextProcess()
 {
     WEBRTC_TRACE(
         kTraceWarning,
         kTraceFile,
         _id,
         "TimeUntilNextProcess: This method is not used by MediaFile class.");
     return -1;
 }
 
-void MediaFileImpl::Process()
+int32_t MediaFileImpl::Process()
 {
     WEBRTC_TRACE(kTraceWarning, kTraceFile, _id,
                  "Process: This method is not used by MediaFile class.");
+    return -1;
 }
 
 int32_t MediaFileImpl::PlayoutAudioData(int8_t* buffer,
                                         size_t& dataLengthInBytes)
 {
     WEBRTC_TRACE(kTraceStream, kTraceFile, _id,
                "MediaFileImpl::PlayoutData(buffer= 0x%x, bufLen= %" PRIuS ")",
                  buffer, dataLengthInBytes);
 
     const size_t bufferLengthInBytes = dataLengthInBytes;
@@ skipping 1015 matching lines @@
 {
     if((frequency == 8000) || (frequency == 16000)|| (frequency == 32000))
     {
         return true;
     }
     WEBRTC_TRACE(kTraceError, kTraceFile, -1,
                  "Frequency should be 8000, 16000 or 32000 (Hz)");
     return false;
 }
 }  // namespace webrtc