Revert of Remove the deprecated EncodeInternal interface from AudioEncoder

webrtc/modules/audio_coding/codecs/cng/audio_encoder_cng.cc

Index: webrtc/modules/audio_coding/codecs/cng/audio_encoder_cng.cc
diff --git a/webrtc/modules/audio_coding/codecs/cng/audio_encoder_cng.cc b/webrtc/modules/audio_coding/codecs/cng/audio_encoder_cng.cc
index 0fa9d9e789cc37813bd1e247b569e7ed9698a367..3b48131a754e7f33ce8ded0d5cb259e584d7ae93 100644
--- a/webrtc/modules/audio_coding/codecs/cng/audio_encoder_cng.cc
+++ b/webrtc/modules/audio_coding/codecs/cng/audio_encoder_cng.cc
@@ -81,6 +81,13 @@
 }
 
 AudioEncoderCng::~AudioEncoderCng() = default;
+
+size_t AudioEncoderCng::MaxEncodedBytes() const {
+  const size_t max_encoded_bytes_active = speech_encoder_->MaxEncodedBytes();
+  const size_t max_encoded_bytes_passive =
+      rtc::CheckedDivExact(kMaxFrameSizeMs, 10) * SamplesPer10msFrame();
+  return std::max(max_encoded_bytes_active, max_encoded_bytes_passive);
+}
 
 int AudioEncoderCng::SampleRateHz() const {
   return speech_encoder_->SampleRateHz();