This CL adds the basic framework for AEC3 in the audio processing module.
It will be followed by a number of other CLs that extends this framework.

BUG=webrtc:6018

Review-Url: https://codereview.webrtc.org/2567513003
Cr-Commit-Position: refs/heads/master@{#15593}
diff --git a/webrtc/modules/audio_processing/include/config.h b/webrtc/modules/audio_processing/include/config.h
index 615e3fa..0473d2d 100644
--- a/webrtc/modules/audio_processing/include/config.h
+++ b/webrtc/modules/audio_processing/include/config.h
@@ -24,16 +24,16 @@
   kMyExperimentForTest,
   kAlgo1CostFunctionForTest,
   kTemporalLayersFactory,  // Deprecated
-  kNetEqCapacityConfig,  // Deprecated
-  kNetEqFastAccelerate,  // Deprecated
-  kVoicePacing,  // Deprecated
+  kNetEqCapacityConfig,    // Deprecated
+  kNetEqFastAccelerate,    // Deprecated
+  kVoicePacing,            // Deprecated
   kExtendedFilter,
   kDelayAgnostic,
   kExperimentalAgc,
   kExperimentalNs,
   kBeamforming,
   kIntelligibility,
-  kEchoCanceller3,
+  kEchoCanceller3,  // Deprecated
   kAecRefinedAdaptiveFilter,
   kLevelControl
 };