Remove RegisterExternal{De,En}coder error codes.

webrtc/modules/video_coding/include/video_coding.h

 /*
  *  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 163 matching lines @@
     // Register an external encoder object. This can not be used together with
     // external decoder callbacks.
     //
     // Input:
     //      - externalEncoder : Encoder object to be used for encoding frames inserted
     //                          with the AddVideoFrame API.
     //      - payloadType     : The payload type bound which this encoder is bound to.
     //
     // Return value      : VCM_OK, on success.
     //                     < 0,    on error.
+    // TODO(pbos): Remove return type when unused elsewhere.
     virtual int32_t RegisterExternalEncoder(VideoEncoder* externalEncoder,
                                             uint8_t payloadType,
                                             bool internalSource = false) = 0;
 
     // API to get currently configured encoder target bitrate in bits/s.
     //
     // Return value      : 0,   on success.
     //                     < 0, on error.
     virtual int Bitrate(unsigned int* bitrate) const = 0;
 
@@ skipping 133 matching lines @@
     // Register an externally defined decoder/renderer object. Can be a decoder only or a
     // decoder coupled with a renderer. Note that RegisterReceiveCodec must be called to
     // be used for decoding incoming streams.
     //
     // Input:
     //      - externalDecoder        : The external decoder/renderer object.
     //      - payloadType            : The payload type which this decoder should be
     //                                 registered to.
     //      - internalRenderTiming   : True if the internal renderer (if any) of the decoder
     //                                 object can make sure to render at a given time in ms.
-    //
-    // Return value      : VCM_OK, on success.
-    //                     < 0,    on error.
-    virtual int32_t RegisterExternalDecoder(VideoDecoder* externalDecoder,
-                                            uint8_t payloadType,
-                                            bool internalRenderTiming) = 0;
+    virtual void RegisterExternalDecoder(VideoDecoder* externalDecoder,
+                                         uint8_t payloadType,
+                                         bool internalRenderTiming) = 0;
 
     // Register a receive callback. Will be called whenever there is a new frame ready
     // for rendering.
     //
     // Input:
     //      - receiveCallback        : The callback object to be used by the module when a
     //                                 frame is ready for rendering.
     //                                 De-register with a NULL pointer.
     //
     // Return value      : VCM_OK, on success.
@@ skipping 182 matching lines @@
         EncodedImageCallback* observer) = 0;
     virtual void RegisterPostEncodeImageCallback(
         EncodedImageCallback* post_encode_callback) = 0;
     // Releases pending decode calls, permitting faster thread shutdown.
     virtual void TriggerDecoderShutdown() = 0;
 };
 
 }  // namespace webrtc
 
 #endif // WEBRTC_MODULES_VIDEO_CODING_INCLUDE_VIDEO_CODING_H_