Hide ACMCodecDB::codec_settings_ behind an accessor

webrtc/modules/audio_coding/main/acm2/rent_a_codec.cc

 /*
  *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 32 matching lines @@
   // will be the same value as in default codec settings, but not for all.
   ci->channels = channels;
 
   return ci;
 }
 
 bool RentACodec::IsCodecValid(const CodecInst& codec_inst) {
   return ACMCodecDB::CodecNumber(codec_inst) >= 0;
 }
 
+rtc::Maybe<bool> RentACodec::IsSupportedNumChannels(CodecId codec_id,
+                                                    int num_channels) {
+  auto i = CodecIndexFromId(codec_id);
+  return i ? rtc::Maybe<bool>(ACMCodecDB::codec_settings_[*i].channel_support >=
+                              num_channels)
+           : rtc::Maybe<bool>();
+}
+
 rtc::ArrayView<const CodecInst> RentACodec::Database() {
   return rtc::ArrayView<const CodecInst>(ACMCodecDB::database_,
                                          NumberOfCodecs());
 }
 
 rtc::Maybe<NetEqDecoder> RentACodec::NetEqDecoderFromCodecId(CodecId codec_id,
                                                              int num_channels) {
   rtc::Maybe<int> i = CodecIndexFromId(codec_id);
   if (!i)
     return rtc::Maybe<NetEqDecoder>();
   const NetEqDecoder ned = ACMCodecDB::neteq_decoders_[*i];
   return rtc::Maybe<NetEqDecoder>(
       (ned == NetEqDecoder::kDecoderOpus && num_channels == 2)
           ? NetEqDecoder::kDecoderOpus_2ch
           : ned);
 }
 
 }  // namespace acm2
 }  // namespace webrtc