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

webrtc/modules/audio_processing/aec3/aec3_constants.h

Index: webrtc/modules/audio_processing/aec3/aec3_constants.h
diff --git a/webrtc/modules/audio_processing/aec3/aec3_constants.h b/webrtc/modules/audio_processing/aec3/aec3_constants.h
index 946e50c78636584ba4cd1da24c73185271a27887..054b0d8afd8fcf0086bac867c67f2aa1cef8dc42 100644
--- a/webrtc/modules/audio_processing/aec3/aec3_constants.h
+++ b/webrtc/modules/audio_processing/aec3/aec3_constants.h
@@ -34,6 +34,11 @@ constexpr int LowestBandRate(int sample_rate_hz) {
   return sample_rate_hz == 8000 ? sample_rate_hz : 16000;
 }
 
+constexpr bool ValidFullBandRate(int sample_rate_hz) {
+  return sample_rate_hz == 8000 || sample_rate_hz == 16000 ||
+         sample_rate_hz == 32000 || sample_rate_hz == 48000;
+}
+
 static_assert(1 == NumBandsForRate(8000), "Number of bands for 8 kHz");
 static_assert(1 == NumBandsForRate(16000), "Number of bands for 16 kHz");
 static_assert(2 == NumBandsForRate(32000), "Number of bands for 32 kHz");
@@ -47,6 +52,17 @@ static_assert(16000 == LowestBandRate(32000),
 static_assert(16000 == LowestBandRate(48000),
               "Sample rate of band 0 for 48 kHz");
 
+static_assert(ValidFullBandRate(8000),
+              "Test that 8 kHz is a valid sample rate");
+static_assert(ValidFullBandRate(16000),
+              "Test that 16 kHz is a valid sample rate");
+static_assert(ValidFullBandRate(32000),
+              "Test that 32 kHz is a valid sample rate");
+static_assert(ValidFullBandRate(48000),
+              "Test that 48 kHz is a valid sample rate");
+static_assert(!ValidFullBandRate(8001),
+              "Test that 8001 Hz is not a valid sample rate");
+
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_AUDIO_PROCESSING_AEC3_AEC3_CONSTANTS_H_