Use propagated field trials for WebRTC-NormalizeSimulcastResolution experiment

Bug: webrtc:10335
Change-Id: I2db0ac9fc305e033c26cb8401db38317fbc71014
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/343761
Reviewed-by: Åsa Persson <asapersson@webrtc.org>
Commit-Queue: Åsa Persson <asapersson@webrtc.org>
Auto-Submit: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#41934}

rtc_base/experiments/BUILD.gn

@@ -117,7 +117,7 @@ rtc_library("normalize_simulcast_size_experiment") {
   ]
   deps = [
     "..:logging",
-    "../../system_wrappers:field_trial",
+    "../../api:field_trials_view",
   ]
   absl_deps = [ "//third_party/abseil-cpp/absl/types:optional" ]
 }
@@ -287,6 +287,7 @@ if (rtc_include_tests && !build_with_chromium) {
       "../../api/video:video_frame",
       "../../api/video_codecs:video_codecs_api",
       "../../system_wrappers:field_trial",
+      "../../test:explicit_key_value_config",
       "../../test:field_trial",
       "../../test:scoped_key_value_config",
       "../../test:test_main",

rtc_base/experiments/normalize_simulcast_size_experiment.cc

@@ -14,8 +14,8 @@
 
 #include <string>
 
+#include "api/field_trials_view.h"
 #include "rtc_base/logging.h"
-#include "system_wrappers/include/field_trial.h"
 
 namespace webrtc {
 namespace {
@@ -24,11 +24,12 @@ constexpr int kMinSetting = 0;
 constexpr int kMaxSetting = 5;
 }  // namespace
 
-absl::optional<int> NormalizeSimulcastSizeExperiment::GetBase2Exponent() {
-  if (!webrtc::field_trial::IsEnabled(kFieldTrial))
+absl::optional<int> NormalizeSimulcastSizeExperiment::GetBase2Exponent(
+    const FieldTrialsView& field_trials) {
+  if (!field_trials.IsEnabled(kFieldTrial))
     return absl::nullopt;
 
-  const std::string group = webrtc::field_trial::FindFullName(kFieldTrial);
+  const std::string group = field_trials.Lookup(kFieldTrial);
   if (group.empty())
     return absl::nullopt;
 

rtc_base/experiments/normalize_simulcast_size_experiment.h

@@ -12,12 +12,14 @@
 #define RTC_BASE_EXPERIMENTS_NORMALIZE_SIMULCAST_SIZE_EXPERIMENT_H_
 
 #include "absl/types/optional.h"
+#include "api/field_trials_view.h"
 
 namespace webrtc {
 class NormalizeSimulcastSizeExperiment {
  public:
   // Returns the base two exponent from field trial.
-  static absl::optional<int> GetBase2Exponent();
+  static absl::optional<int> GetBase2Exponent(
+      const FieldTrialsView& field_trials);
 };
 
 }  // namespace webrtc

rtc_base/experiments/normalize_simulcast_size_experiment_unittest.cc

@@ -10,50 +10,58 @@
 
 #include "rtc_base/experiments/normalize_simulcast_size_experiment.h"
 
-#include "test/field_trial.h"
+#include "test/explicit_key_value_config.h"
 #include "test/gtest.h"
 
 namespace webrtc {
 
+using test::ExplicitKeyValueConfig;
+
 TEST(NormalizeSimulcastSizeExperimentTest, GetExponent) {
-  webrtc::test::ScopedFieldTrials field_trials(
+  ExplicitKeyValueConfig field_trials(
       "WebRTC-NormalizeSimulcastResolution/Enabled-2/");
-  EXPECT_EQ(2, NormalizeSimulcastSizeExperiment::GetBase2Exponent());
+  EXPECT_EQ(2,
+            NormalizeSimulcastSizeExperiment::GetBase2Exponent(field_trials));
 }
 
 TEST(NormalizeSimulcastSizeExperimentTest, GetExponentWithTwoParameters) {
-  webrtc::test::ScopedFieldTrials field_trials(
+  ExplicitKeyValueConfig field_trials(
       "WebRTC-NormalizeSimulcastResolution/Enabled-3-4/");
-  EXPECT_EQ(3, NormalizeSimulcastSizeExperiment::GetBase2Exponent());
+  EXPECT_EQ(3,
+            NormalizeSimulcastSizeExperiment::GetBase2Exponent(field_trials));
 }
 
 TEST(NormalizeSimulcastSizeExperimentTest, GetExponentFailsIfNotEnabled) {
-  webrtc::test::ScopedFieldTrials field_trials(
+  ExplicitKeyValueConfig field_trials(
       "WebRTC-NormalizeSimulcastResolution/Disabled/");
-  EXPECT_FALSE(NormalizeSimulcastSizeExperiment::GetBase2Exponent());
+  EXPECT_FALSE(
+      NormalizeSimulcastSizeExperiment::GetBase2Exponent(field_trials));
 }
 
 TEST(NormalizeSimulcastSizeExperimentTest,
      GetExponentFailsForInvalidFieldTrial) {
-  webrtc::test::ScopedFieldTrials field_trials(
+  ExplicitKeyValueConfig field_trials(
       "WebRTC-NormalizeSimulcastResolution/Enabled-invalid/");
-  EXPECT_FALSE(NormalizeSimulcastSizeExperiment::GetBase2Exponent());
+  EXPECT_FALSE(
+      NormalizeSimulcastSizeExperiment::GetBase2Exponent(field_trials));
 }
 
 TEST(NormalizeSimulcastSizeExperimentTest,
      GetExponentFailsForNegativeOutOfBoundValue) {
   // Supported range: [0, 5].
-  webrtc::test::ScopedFieldTrials field_trials(
+  ExplicitKeyValueConfig field_trials(
       "WebRTC-NormalizeSimulcastResolution/Enabled--1/");
-  EXPECT_FALSE(NormalizeSimulcastSizeExperiment::GetBase2Exponent());
+  EXPECT_FALSE(
+      NormalizeSimulcastSizeExperiment::GetBase2Exponent(field_trials));
 }
 
 TEST(NormalizeSimulcastSizeExperimentTest,
      GetExponentFailsForPositiveOutOfBoundValue) {
   // Supported range: [0, 5].
-  webrtc::test::ScopedFieldTrials field_trials(
+  ExplicitKeyValueConfig field_trials(
       "WebRTC-NormalizeSimulcastResolution/Enabled-6/");
-  EXPECT_FALSE(NormalizeSimulcastSizeExperiment::GetBase2Exponent());
+  EXPECT_FALSE(
+      NormalizeSimulcastSizeExperiment::GetBase2Exponent(field_trials));
 }
 
 }  // namespace webrtc

video/config/encoder_stream_factory.cc

@@ -340,16 +340,19 @@ EncoderStreamFactory::CreateSimulcastOrConferenceModeScreenshareStreams(
     default_scale_factors_used = IsScaleFactorsPowerOfTwo(encoder_config);
   }
   const bool norm_size_configured =
-      webrtc::NormalizeSimulcastSizeExperiment::GetBase2Exponent().has_value();
+      webrtc::NormalizeSimulcastSizeExperiment::GetBase2Exponent(trials_)
+          .has_value();
   const int normalized_width =
       (default_scale_factors_used || norm_size_configured) &&
               (width >= kMinLayerSize)
-          ? NormalizeSimulcastSize(width, encoder_config.number_of_streams)
+          ? NormalizeSimulcastSize(trials_, width,
+                                   encoder_config.number_of_streams)
           : width;
   const int normalized_height =
       (default_scale_factors_used || norm_size_configured) &&
               (height >= kMinLayerSize)
-          ? NormalizeSimulcastSize(height, encoder_config.number_of_streams)
+          ? NormalizeSimulcastSize(trials_, height,
+                                   encoder_config.number_of_streams)
           : height;
   for (size_t i = 0; i < layers.size(); ++i) {
     layers[i].active = encoder_config.simulcast_layers[i].active;

video/config/simulcast.cc

@@ -19,6 +19,7 @@
 
 #include "absl/strings/match.h"
 #include "absl/types/optional.h"
+#include "api/field_trials_view.h"
 #include "api/video/video_codec_constants.h"
 #include "media/base/media_constants.h"
 #include "modules/video_coding/utility/simulcast_rate_allocator.h"
@@ -33,6 +34,8 @@ namespace cricket {
 
 namespace {
 
+using ::webrtc::FieldTrialsView;
+
 constexpr char kUseLegacySimulcastLayerLimitFieldTrial[] =
     "WebRTC-LegacySimulcastLayerLimit";
 
@@ -218,10 +221,12 @@ int FindSimulcastFormatIndex(int width,
 // Round size to nearest simulcast-friendly size.
 // Simulcast stream width and height must both be dividable by
 // |2 ^ (simulcast_layers - 1)|.
-int NormalizeSimulcastSize(int size, size_t simulcast_layers) {
+int NormalizeSimulcastSize(const FieldTrialsView& field_trials,
+                           int size,
+                           size_t simulcast_layers) {
   int base2_exponent = static_cast<int>(simulcast_layers) - 1;
   const absl::optional<int> experimental_base2_exponent =
-      webrtc::NormalizeSimulcastSizeExperiment::GetBase2Exponent();
+      webrtc::NormalizeSimulcastSizeExperiment::GetBase2Exponent(field_trials);
   if (experimental_base2_exponent &&
       (size > (1 << *experimental_base2_exponent))) {
     base2_exponent = *experimental_base2_exponent;
@@ -411,8 +416,8 @@ std::vector<webrtc::VideoStream> GetNormalSimulcastLayers(
   const int num_temporal_layers = DefaultNumberOfTemporalLayers(trials);
   // Format width and height has to be divisible by |2 ^ num_simulcast_layers -
   // 1|.
-  width = NormalizeSimulcastSize(width, layer_count);
-  height = NormalizeSimulcastSize(height, layer_count);
+  width = NormalizeSimulcastSize(trials, width, layer_count);
+  height = NormalizeSimulcastSize(trials, height, layer_count);
   // Add simulcast streams, from highest resolution (`s` = num_simulcast_layers
   // -1) to lowest resolution at `s` = 0.
   for (size_t s = layer_count - 1;; --s) {

video/config/simulcast.h

@@ -31,7 +31,9 @@ void BoostMaxSimulcastLayer(webrtc::DataRate max_bitrate,
                             std::vector<webrtc::VideoStream>* layers);
 
 // Round size to nearest simulcast-friendly size
-int NormalizeSimulcastSize(int size, size_t simulcast_layers);
+int NormalizeSimulcastSize(const webrtc::FieldTrialsView& field_trials,
+                           int size,
+                           size_t simulcast_layers);
 
 // Gets simulcast settings.
 std::vector<webrtc::VideoStream> GetSimulcastConfig(