Move VideoDecoder::Create() logic to separate internal video decoder factory

webrtc/video_decoder.h

 /*
  *  Copyright (c) 2014 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 32 matching lines @@
 
   virtual int32_t ReceivedDecodedReferenceFrame(const uint64_t pictureId) {
     return -1;
   }
 
   virtual int32_t ReceivedDecodedFrame(const uint64_t pictureId) { return -1; }
 };
 
 class VideoDecoder {
  public:
-  enum DecoderType {
-    kH264,
-    kVp8,
-    kVp9,
-    kUnsupportedCodec,
-  };
-
-  static VideoDecoder* Create(DecoderType codec_type);
-
   virtual ~VideoDecoder() {}
 
   virtual int32_t InitDecode(const VideoCodec* codec_settings,
                              int32_t number_of_cores) = 0;
 
   virtual int32_t Decode(const EncodedImage& input_image,
                          bool missing_frames,
                          const RTPFragmentationHeader* fragmentation,
                          const CodecSpecificInfo* codec_specific_info = NULL,
                          int64_t render_time_ms = -1) = 0;
 
   virtual int32_t RegisterDecodeCompleteCallback(
       DecodedImageCallback* callback) = 0;
 
   virtual int32_t Release() = 0;
 
   // Returns true if the decoder prefer to decode frames late.
   // That is, it can not decode infinite number of frames before the decoded
   // frame is consumed.
   virtual bool PrefersLateDecoding() const { return true; }
 
   virtual const char* ImplementationName() const { return "unknown"; }
 };
 
-// Video decoder class to be used for unknown codecs. Doesn't support decoding
-// but logs messages to LS_ERROR.
-class NullVideoDecoder : public VideoDecoder {
- public:
-  NullVideoDecoder();
-
-  int32_t InitDecode(const VideoCodec* codec_settings,
-                     int32_t number_of_cores) override;
-
-  int32_t Decode(const EncodedImage& input_image,
-                 bool missing_frames,
-                 const RTPFragmentationHeader* fragmentation,
-                 const CodecSpecificInfo* codec_specific_info,
-                 int64_t render_time_ms) override;
-
-  int32_t RegisterDecodeCompleteCallback(
-      DecodedImageCallback* callback) override;
-
-  int32_t Release() override;
-
-  const char* ImplementationName() const override;
-};
-
 }  // namespace webrtc
 
 #endif  // WEBRTC_VIDEO_DECODER_H_