Remove expired field trial UseTwccPlrForAna

Bug: webrtc:7058
Change-Id: I432d0df9cdf53d2de4e4b33a59807787c5a55772
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/345480
Reviewed-by: Jakob Ivarsson‎ <[email protected]>
Commit-Queue: Emil Lundmark <[email protected]>
Reviewed-by: Elad Alon <[email protected]>
Cr-Commit-Position: refs/heads/main@{#42064}

Author: lndmrk

experiments/field_trials.py

@@ -164,9 +164,6 @@ def bug_url(self) -> str:
 # POLICY_EXEMPT_FIELD_TRIALS_DIGEST.
 POLICY_EXEMPT_FIELD_TRIALS: FrozenSet[FieldTrial] = frozenset([
     # keep-sorted start
-    FieldTrial('UseTwccPlrForAna',
-               'webrtc:7058',
-               date(2024, 4, 1)),
     FieldTrial('WebRTC-AddNetworkCostToVpn',
                'webrtc:13097',
                date(2024, 4, 1)),
@@ -914,7 +911,7 @@ def bug_url(self) -> str:
 ])  # yapf: disable
 
 POLICY_EXEMPT_FIELD_TRIALS_DIGEST: str = \
-    '023f4ce749a699f0ab811093b9f568d604da28a8'
+    '3026f839766eb90355893fa0f1af8e9bf0d0dca1'
 
 REGISTERED_FIELD_TRIALS: FrozenSet[FieldTrial] = ACTIVE_FIELD_TRIALS.union(
     POLICY_EXEMPT_FIELD_TRIALS)

modules/audio_coding/audio_network_adaptor/fec_controller_plr_based.cc

@@ -14,27 +14,9 @@
 #include <utility>
 
 #include "rtc_base/checks.h"
-#include "system_wrappers/include/field_trial.h"
 
 namespace webrtc {
 
-namespace {
-class NullSmoothingFilter final : public SmoothingFilter {
- public:
-  void AddSample(float sample) override { last_sample_ = sample; }
-
-  absl::optional<float> GetAverage() override { return last_sample_; }
-
-  bool SetTimeConstantMs(int time_constant_ms) override {
-    RTC_DCHECK_NOTREACHED();
-    return false;
-  }
-
- private:
-  absl::optional<float> last_sample_;
-};
-}  // namespace
-
 FecControllerPlrBased::Config::Config(
     bool initial_fec_enabled,
     const ThresholdCurve& fec_enabling_threshold,
@@ -57,10 +39,7 @@ FecControllerPlrBased::FecControllerPlrBased(
 FecControllerPlrBased::FecControllerPlrBased(const Config& config)
     : FecControllerPlrBased(
           config,
-          webrtc::field_trial::FindFullName("UseTwccPlrForAna") == "Enabled"
-              ? std::unique_ptr<NullSmoothingFilter>(new NullSmoothingFilter())
-              : std::unique_ptr<SmoothingFilter>(
-                    new SmoothingFilterImpl(config.time_constant_ms))) {}
+          std::make_unique<SmoothingFilterImpl>(config.time_constant_ms)) {}
 
 FecControllerPlrBased::~FecControllerPlrBased() = default;