Deprecate VideoDecoder::Reset() and remove calls.

webrtc/video/vie_channel.cc

Index: webrtc/video/vie_channel.cc
diff --git a/webrtc/video/vie_channel.cc b/webrtc/video/vie_channel.cc
index b1b0f0c4b8dcc8ef4e3bcde19de7e47c60af1b83..bbc28708568516c35ff70b992a81285d457f0f2a 100644
--- a/webrtc/video/vie_channel.cc
+++ b/webrtc/video/vie_channel.cc
@@ -914,10 +914,8 @@ void ViEChannel::StartReceive() {
 
 void ViEChannel::StopReceive() {
   vie_receiver_.StopReceive();
-  if (!sender_) {
+  if (!sender_)
     StopDecodeThread();
-    vcm_->ResetDecoder();

[stefan-webrtc, 2016/02/01 16:23:08]

Is this safe to remove? I assume it is, but it would be good if you explained
why you think it is. 

[pbos-webrtc, 2016/02/02 13:25:12]

Yeah, I don't think there's any point in killing the decoder here, if we don't
then it doesn't have to reinitialize if it starts receiving again.

-  }
 }
 
 int32_t ViEChannel::ReceivedRTPPacket(const void* rtp_packet,
@@ -1166,8 +1164,8 @@ void ViEChannel::RegisterPreDecodeImageCallback(
   vcm_->RegisterPreDecodeImageCallback(pre_decode_callback);
 }
 
-// TODO(pbos): Remove OnInitializeDecoder which is called from the RTP module,
-// any decoder resetting should be handled internally within the VCM.
+// TODO(pbos): Consider updating callback to contain video resolution so we can
+// initialize the decoder earlier here.
 int32_t ViEChannel::OnInitializeDecoder(
     const int8_t payload_type,
     const char payload_name[RTP_PAYLOAD_NAME_SIZE],
@@ -1176,8 +1174,6 @@ int32_t ViEChannel::OnInitializeDecoder(
     const uint32_t rate) {
   LOG(LS_INFO) << "OnInitializeDecoder " << static_cast<int>(payload_type)
                << " " << payload_name;
-  vcm_->ResetDecoder();
-
   return 0;

[stefan-webrtc, 2016/02/01 16:23:08]

This change doesn't seem trivial to me. Should we instead do an InitEncode()?
Are we guaranteed to do that InitEncode/Reset once a frame gets to the decoder?
For instance, I'm not sure we have checks on payload type change in the VCM, so
if we switch payload type maybe we don't reset the decoder now?

[pbos-webrtc, 2016/02/02 13:25:12]

Decode in VideoReceiver calls VCMCodecDataBase::GetDecoder which reinitializes
if payload_type has changed, the only difference here is that it will do a
decoder release on the network(?) thread.

 }