Adding full initial version of delay estimation functionality in echo canceller 3

webrtc/modules/audio_processing/aec3/echo_remover.cc

Index: webrtc/modules/audio_processing/aec3/echo_remover.cc
diff --git a/webrtc/modules/audio_processing/aec3/echo_remover.cc b/webrtc/modules/audio_processing/aec3/echo_remover.cc
index 2ae5525b4a7510a46a7f7701bf3d6e39404e9f63..ab0b68bb168f5b60b14cd02dd89d510c908721f0 100644
--- a/webrtc/modules/audio_processing/aec3/echo_remover.cc
+++ b/webrtc/modules/audio_processing/aec3/echo_remover.cc
@@ -42,8 +42,7 @@ class EchoRemoverImpl final : public EchoRemover {
 // TODO(peah): Add functionality.
 EchoRemoverImpl::EchoRemoverImpl(int sample_rate_hz)
     : sample_rate_hz_(sample_rate_hz) {
-  RTC_DCHECK(sample_rate_hz == 8000 || sample_rate_hz == 16000 ||
-             sample_rate_hz == 32000 || sample_rate_hz == 48000);
+  RTC_DCHECK(ValidFullBandRate(sample_rate_hz_));
 }
 
 EchoRemoverImpl::~EchoRemoverImpl() = default;