Enable AEC in lacros-chrome

Make acros-chrome able to use AEC. The code is modified from
audio_manager_chromeos.

BUG=b:172639327

Change-Id: I812d1bef12d02ec96dfc5d84783c63dfdd1cfc68
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2522016
Commit-Queue: Yu-Hsuan Hsu <yuhsuan@chromium.org>
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#825184}

media/audio/audio_features.cc

@@ -32,7 +32,7 @@ const base::Feature kUseAAudioDriver{"UseAAudioDriver",
                                      base::FEATURE_ENABLED_BY_DEFAULT};
 #endif
 
-#if BUILDFLAG(IS_ASH)
+#if BUILDFLAG(IS_ASH) || BUILDFLAG(IS_LACROS)
 const base::Feature kCrOSSystemAEC{"CrOSSystemAEC",
                                    base::FEATURE_ENABLED_BY_DEFAULT};
 const base::Feature kCrOSSystemAECDeactivatedGroups{

media/audio/audio_features.h

@@ -19,7 +19,7 @@ MEDIA_EXPORT extern const base::Feature kDumpOnAudioServiceHang;
 MEDIA_EXPORT extern const base::Feature kUseAAudioDriver;
 #endif
 
-#if BUILDFLAG(IS_ASH)
+#if BUILDFLAG(IS_ASH) || BUILDFLAG(IS_LACROS)
 MEDIA_EXPORT extern const base::Feature kCrOSSystemAEC;
 MEDIA_EXPORT extern const base::Feature kCrOSSystemAECDeactivatedGroups;
 #endif

media/audio/cras/audio_manager_cras.cc

@@ -91,6 +91,28 @@ AudioParameters AudioManagerCras::GetInputStreamParameters(
       kDefaultSampleRate, buffer_size,
       AudioParameters::HardwareCapabilities(limits::kMinAudioBufferSize,
                                             limits::kMaxAudioBufferSize));
+
+  // Allow experimentation with system echo cancellation with all devices,
+  // but enable it by default on devices that actually support it.
+  params.set_effects(params.effects() |
+                     AudioParameters::EXPERIMENTAL_ECHO_CANCELLER);
+  if (base::FeatureList::IsEnabled(features::kCrOSSystemAEC)) {
+    if (CrasGetAecSupported()) {
+      const int32_t aec_group_id = CrasGetAecGroupId();
+
+      // Check if the system AEC has a group ID which is flagged to be
+      // deactivated by the field trial.
+      const bool system_aec_deactivated =
+          base::GetFieldTrialParamByFeatureAsBool(
+              features::kCrOSSystemAECDeactivatedGroups,
+              base::NumberToString(aec_group_id), false);
+
+      if (!system_aec_deactivated) {
+        params.set_effects(params.effects() | AudioParameters::ECHO_CANCELLER);
+      }
+    }
+  }
+
   return params;
 }
 

media/audio/cras/cras_util.cc

@@ -108,4 +108,25 @@ std::vector<CrasDevice> CrasGetAudioDevices(DeviceType type) {
   return devices;
 }
 
+int CrasGetAecSupported() {
+  cras_client* client = CrasConnect();
+  if (!client)
+    return 0;
+
+  int rc = cras_client_get_aec_supported(client);
+  CrasDisconnect(&client);
+  return rc;
+}
+
+int CrasGetAecGroupId() {
+  cras_client* client = CrasConnect();
+  if (!client)
+    return -1;
+
+  int rc = cras_client_get_aec_group_id(client);
+  CrasDisconnect(&client);
+
+  return rc;
+}
+
 }  // namespace media

media/audio/cras/cras_util.h

@@ -28,6 +28,13 @@ struct CrasDevice {
 // Enumerates all devices of |type|.
 std::vector<CrasDevice> CrasGetAudioDevices(DeviceType type);
 
+// Returns if system AEC is supported in CRAS.
+int CrasGetAecSupported();
+
+// Returns the system AEC group ID. If no group ID is specified, -1 is
+// returned.
+int CrasGetAecGroupId();
+
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_CRAS_CRAS_UTIL_H_