Re-land: "Use an explicit identifier in Config"

webrtc/modules/audio_processing/include/audio_processing.h

Index: webrtc/modules/audio_processing/include/audio_processing.h
diff --git a/webrtc/modules/audio_processing/include/audio_processing.h b/webrtc/modules/audio_processing/include/audio_processing.h
index 5dd63ebc303bc82ea7b654baebb7f8eb5009664a..9a3a4b32d50d6054bdf88b6684d72b21e859ebb6 100644
--- a/webrtc/modules/audio_processing/include/audio_processing.h
+++ b/webrtc/modules/audio_processing/include/audio_processing.h
@@ -65,6 +65,7 @@ class VoiceDetection;
 struct ExtendedFilter {
   ExtendedFilter() : enabled(false) {}
   explicit ExtendedFilter(bool enabled) : enabled(enabled) {}
+  static const ConfigOptionID identifier = ConfigOptionID::kExtendedFilter;
   bool enabled;
 };
 
@@ -76,6 +77,7 @@ struct ExtendedFilter {
 struct DelayAgnostic {
   DelayAgnostic() : enabled(false) {}
   explicit DelayAgnostic(bool enabled) : enabled(enabled) {}
+  static const ConfigOptionID identifier = ConfigOptionID::kDelayAgnostic;
   bool enabled;
 };
 
@@ -96,6 +98,7 @@ struct ExperimentalAgc {
       : enabled(enabled), startup_min_volume(kAgcStartupMinVolume) {}
   ExperimentalAgc(bool enabled, int startup_min_volume)
       : enabled(enabled), startup_min_volume(startup_min_volume) {}
+  static const ConfigOptionID identifier = ConfigOptionID::kExperimentalAgc;
   bool enabled;
   int startup_min_volume;
 };
@@ -105,6 +108,7 @@ struct ExperimentalAgc {
 struct ExperimentalNs {
   ExperimentalNs() : enabled(false) {}
   explicit ExperimentalNs(bool enabled) : enabled(enabled) {}
+  static const ConfigOptionID identifier = ConfigOptionID::kExperimentalNs;
   bool enabled;
 };
 
@@ -127,6 +131,7 @@ struct Beamforming {
       : enabled(enabled),
         array_geometry(array_geometry),
         target_direction(target_direction) {}
+  static const ConfigOptionID identifier = ConfigOptionID::kBeamforming;
   const bool enabled;
   const std::vector<Point> array_geometry;
   const SphericalPointf target_direction;
@@ -141,6 +146,7 @@ struct Beamforming {
 struct Intelligibility {
   Intelligibility() : enabled(false) {}
   explicit Intelligibility(bool enabled) : enabled(enabled) {}
+  static const ConfigOptionID identifier = ConfigOptionID::kIntelligibility;
   bool enabled;
 };