Don't re-randomize picture_id/tl0_pic_idx when re-initializing internal encoders.

webrtc/modules/video_coding/codecs/vp9/vp9_impl.h

Index: webrtc/modules/video_coding/codecs/vp9/vp9_impl.h
diff --git a/webrtc/modules/video_coding/codecs/vp9/vp9_impl.h b/webrtc/modules/video_coding/codecs/vp9/vp9_impl.h
index 8b92b06f878ff7902955e09597b6edcc67d0e526..7555ccbf58a9a6c765b458bf8e305dbb305bbfa0 100644
--- a/webrtc/modules/video_coding/codecs/vp9/vp9_impl.h
+++ b/webrtc/modules/video_coding/codecs/vp9/vp9_impl.h
@@ -107,7 +107,6 @@ class VP9EncoderImpl : public VP9Encoder {
   VideoCodec codec_;
   bool inited_;
   int64_t timestamp_;
-  uint16_t picture_id_;
   int cpu_speed_;
   uint32_t rc_max_intra_target_;
   vpx_codec_ctx_t* encoder_;
@@ -117,7 +116,6 @@ class VP9EncoderImpl : public VP9Encoder {
   const VideoFrame* input_image_;
   GofInfoVP9 gof_;       // Contains each frame's temporal information for
                          // non-flexible mode.
-  uint8_t tl0_pic_idx_;  // Only used in non-flexible mode.
   size_t frames_since_kf_;
   uint8_t num_temporal_layers_;
   uint8_t num_spatial_layers_;
@@ -129,6 +127,10 @@ class VP9EncoderImpl : public VP9Encoder {
   uint8_t num_ref_pics_[kMaxVp9NumberOfSpatialLayers];
   uint8_t p_diff_[kMaxVp9NumberOfSpatialLayers][kMaxVp9RefPics];
   std::unique_ptr<ScreenshareLayersVP9> spatial_layer_;
+
+  // RTP state.
+  uint16_t picture_id_;
+  uint8_t tl0_pic_idx_;  // Only used in non-flexible mode.
 };
 
 class VP9DecoderImpl : public VP9Decoder {