Fixing init time error in smoothing filter.

webrtc/common_audio/smoothing_filter.h

Index: webrtc/common_audio/smoothing_filter.h
diff --git a/webrtc/common_audio/smoothing_filter.h b/webrtc/common_audio/smoothing_filter.h
index 4967a34442313a62bfc5c0b74515077f718d9df8..4a0efd99b6d5fa605a5e82c3157a638b449d0636 100644
--- a/webrtc/common_audio/smoothing_filter.h
+++ b/webrtc/common_audio/smoothing_filter.h
@@ -59,7 +59,7 @@ class SmoothingFilterImpl final : public SmoothingFilter {
   const float init_const_;
   const Clock* const clock_;
 
-  rtc::Optional<int64_t> first_sample_time_ms_;
+  rtc::Optional<int64_t> init_end_time_ms_;
   float last_sample_;
   float alpha_;
   float state_;