Delete unused support for vp8 partitions.

webrtc/modules/video_coding/generic_decoder.cc

Index: webrtc/modules/video_coding/generic_decoder.cc
diff --git a/webrtc/modules/video_coding/generic_decoder.cc b/webrtc/modules/video_coding/generic_decoder.cc
index 38bdb69245028a3ca2e4f8513bc49ff4b245df25..ace826602fcd8e721c48c57c2b4bcb96fc5ae4ac 100644
--- a/webrtc/modules/video_coding/generic_decoder.cc
+++ b/webrtc/modules/video_coding/generic_decoder.cc
@@ -149,8 +149,9 @@ int32_t VCMGenericDecoder::Decode(const VCMEncodedFrame& frame, int64_t nowMs) {
     _callback->Map(frame.TimeStamp(), &_frameInfos[_nextFrameInfoIdx]);
 
     _nextFrameInfoIdx = (_nextFrameInfoIdx + 1) % kDecoderFrameMemoryLength;
+    const RTPFragmentationHeader dummy_header;
     int32_t ret = _decoder->Decode(frame.EncodedImage(), frame.MissingFrame(),
-                                   frame.FragmentationHeader(),
+                                   &dummy_header,
                                    frame.CodecSpecific(), frame.RenderTimeMs());
 
     _callback->OnDecoderImplementationName(_decoder->ImplementationName());