Revert "Use runtime enabled features API to enable dual stream mode"

This reverts commit 6f011dfdd413a903dcdf5a23a49109e64432326d.

Reason for revert: Broke internal builds

Original change's description:
> Use runtime enabled features API to enable dual stream mode
> 
> Bug: webrtc:8287
> Change-Id: I1a366d959a8b7f2a704baa7ea8ace64c1c398d52
> Reviewed-on: https://webrtc-review.googlesource.com/39008
> Commit-Queue: Ilya Nikolaevskiy <ilnik@webrtc.org>
> Reviewed-by: Niels Moller <nisse@webrtc.org>
> Reviewed-by: Philip Eliasson <philipel@webrtc.org>
> Reviewed-by: Patrik Höglund <phoglund@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#21661}

TBR=phoglund@webrtc.org,ilnik@webrtc.org,nisse@webrtc.org,philipel@webrtc.org

Change-Id: I0af406066231b67dd0b8eb6808bdc3e3f77560b6
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: webrtc:8287
Reviewed-on: https://webrtc-review.googlesource.com/40321
Reviewed-by: Lu Liu <lliuu@webrtc.org>
Commit-Queue: Lu Liu <lliuu@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21663}
diff --git a/BUILD.gn b/BUILD.gn
index 9e24f37..bb5c953 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -434,7 +434,6 @@
       "rtc_base:sequenced_task_checker_unittests",
       "rtc_base:weak_ptr_unittests",
       "system_wrappers:metrics_default",
-      "system_wrappers:runtime_enabled_features_default",
     ]
 
     if (rtc_enable_protobuf) {
diff --git a/call/BUILD.gn b/call/BUILD.gn
index 90b44cf..03ed9b4 100644
--- a/call/BUILD.gn
+++ b/call/BUILD.gn
@@ -263,7 +263,6 @@
       "../rtc_base:rtc_base_approved",
       "../system_wrappers",
       "../system_wrappers:metrics_default",
-      "../system_wrappers:runtime_enabled_features_default",
       "../test:direct_transport",
       "../test:fake_audio_device",
       "../test:field_trial",
diff --git a/examples/BUILD.gn b/examples/BUILD.gn
index 1bbcf74..36065e4 100644
--- a/examples/BUILD.gn
+++ b/examples/BUILD.gn
@@ -169,14 +169,12 @@
         ":AppRTCMobile_ios_frameworks",
         "../sdk:common_objc",
         "../system_wrappers:field_trial_default",
-        "../system_wrappers:runtime_enabled_features_default",
       ]
     } else {
       deps = [
         "../sdk:common_objc",
         "../system_wrappers:field_trial_default",
         "../system_wrappers:metrics_default",
-        "../system_wrappers:runtime_enabled_features_default",
       ]
     }
   }
@@ -558,7 +556,6 @@
       "../rtc_base:rtc_json",
       "../system_wrappers:field_trial_default",
       "../system_wrappers:metrics_default",
-      "../system_wrappers:runtime_enabled_features_default",
       "//third_party/libyuv",
     ]
   }
@@ -597,7 +594,6 @@
       "../rtc_base:rtc_base_approved",
       "../system_wrappers:field_trial_default",
       "../system_wrappers:metrics_default",
-      "../system_wrappers:runtime_enabled_features_default",
     ]
     if (!build_with_chromium && is_clang) {
       # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
@@ -616,7 +612,6 @@
       "../rtc_base:rtc_base_approved",
       "../system_wrappers:field_trial_default",
       "../system_wrappers:metrics_default",
-      "../system_wrappers:runtime_enabled_features_default",
     ]
     if (!build_with_chromium && is_clang) {
       # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
@@ -635,7 +630,6 @@
       "../rtc_base:rtc_base_approved",
       "../system_wrappers:field_trial_default",
       "../system_wrappers:metrics_default",
-      "../system_wrappers:runtime_enabled_features_default",
     ]
     if (!build_with_chromium && is_clang) {
       # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
@@ -695,7 +689,6 @@
       "../rtc_base:rtc_base",
       "../system_wrappers:field_trial_default",
       "../system_wrappers:metrics_default",
-      "../system_wrappers:runtime_enabled_features_default",
     ]
     if (is_android) {
       deps += [ "../sdk/android:libjingle_peerconnection_jni" ]
diff --git a/media/BUILD.gn b/media/BUILD.gn
index 9be093c..bfd91ce 100644
--- a/media/BUILD.gn
+++ b/media/BUILD.gn
@@ -612,7 +612,6 @@
       "../rtc_base:rtc_base_tests_main",
       "../rtc_base:rtc_base_tests_utils",
       "../system_wrappers:metrics_default",
-      "../system_wrappers:runtime_enabled_features_default",
       "../test:audio_codec_mocks",
       "../test:test_support",
       "../test:video_test_common",
diff --git a/modules/congestion_controller/BUILD.gn b/modules/congestion_controller/BUILD.gn
index 84de71d..cf303a5 100644
--- a/modules/congestion_controller/BUILD.gn
+++ b/modules/congestion_controller/BUILD.gn
@@ -48,7 +48,6 @@
     "../../system_wrappers",
     "../../system_wrappers:field_trial_api",
     "../../system_wrappers:metrics_api",
-    "../../system_wrappers:runtime_enabled_features_api",
     "../bitrate_controller",
     "../pacing",
     "../remote_bitrate_estimator",
diff --git a/modules/congestion_controller/send_side_congestion_controller.cc b/modules/congestion_controller/send_side_congestion_controller.cc
index cb3e610..2aeed51 100644
--- a/modules/congestion_controller/send_side_congestion_controller.cc
+++ b/modules/congestion_controller/send_side_congestion_controller.cc
@@ -28,7 +28,6 @@
 #include "rtc_base/socket.h"
 #include "rtc_base/timeutils.h"
 #include "system_wrappers/include/field_trial.h"
-#include "system_wrappers/include/runtime_enabled_features.h"
 
 namespace webrtc {
 namespace {
@@ -94,13 +93,6 @@
   std::sort(input->begin(), input->end(), PacketFeedbackComparator());
 }
 
-bool IsPacerPushbackExperimentEnabled() {
-  return webrtc::field_trial::IsEnabled(kPacerPushbackExperiment) || (
-      !webrtc::field_trial::IsDisabled(kPacerPushbackExperiment) &&
-      webrtc::runtime_enabled_features::IsFeatureEnabled(
-          webrtc::runtime_enabled_features::kDualStreamModeFeatureName));
-}
-
 }  // namespace
 
 SendSideCongestionController::SendSideCongestionController(
@@ -132,7 +124,7 @@
       accepted_queue_ms_(kDefaultAcceptedQueueMs),
       was_in_alr_(false),
       pacer_pushback_experiment_(
-          IsPacerPushbackExperimentEnabled()) {
+          webrtc::field_trial::IsEnabled(kPacerPushbackExperiment)) {
   delay_based_bwe_->SetMinBitrate(min_bitrate_bps_);
   if (in_cwnd_experiment_ &&
       !ReadCwndExperimentParameter(&accepted_queue_ms_)) {
diff --git a/modules/pacing/BUILD.gn b/modules/pacing/BUILD.gn
index df83aa5..3734fcf 100644
--- a/modules/pacing/BUILD.gn
+++ b/modules/pacing/BUILD.gn
@@ -43,7 +43,6 @@
     "../../rtc_base/experiments:alr_experiment",
     "../../system_wrappers",
     "../../system_wrappers:field_trial_api",
-    "../../system_wrappers:runtime_enabled_features_api",
     "../remote_bitrate_estimator",
     "../rtp_rtcp",
     "../rtp_rtcp:rtp_rtcp_format",
@@ -70,7 +69,6 @@
       "../../rtc_base/experiments:alr_experiment",
       "../../system_wrappers",
       "../../system_wrappers:field_trial_api",
-      "../../system_wrappers:runtime_enabled_features_api",
       "../../test:field_trial",
       "../../test:test_support",
       "../rtp_rtcp",
diff --git a/modules/pacing/paced_sender.cc b/modules/pacing/paced_sender.cc
index f559ffc..6ca4599 100644
--- a/modules/pacing/paced_sender.cc
+++ b/modules/pacing/paced_sender.cc
@@ -27,7 +27,6 @@
 #include "rtc_base/ptr_util.h"
 #include "system_wrappers/include/clock.h"
 #include "system_wrappers/include/field_trial.h"
-#include "system_wrappers/include/runtime_enabled_features.h"
 
 namespace {
 // Time limit in milliseconds between packet bursts.
@@ -38,15 +37,6 @@
 // time.
 const int64_t kMaxIntervalTimeMs = 30;
 
-const char kRoundRobinExperimentName[] = "WebRTC-RoundRobinPacing";
-
-bool IsRoundRobinPacingEnabled() {
-  return webrtc::field_trial::IsEnabled(kRoundRobinExperimentName) || (
-      !webrtc::field_trial::IsDisabled(kRoundRobinExperimentName) &&
-      webrtc::runtime_enabled_features::IsFeatureEnabled(
-          webrtc::runtime_enabled_features::kDualStreamModeFeatureName));
-}
-
 }  // namespace
 
 namespace webrtc {
@@ -58,7 +48,7 @@
                          PacketSender* packet_sender,
                          RtcEventLog* event_log) :
     PacedSender(clock, packet_sender, event_log,
-                IsRoundRobinPacingEnabled()
+                webrtc::field_trial::IsEnabled("WebRTC-RoundRobinPacing")
                     ? rtc::MakeUnique<PacketQueue2>(clock)
                     : rtc::MakeUnique<PacketQueue>(clock)) {}
 
diff --git a/ortc/BUILD.gn b/ortc/BUILD.gn
index 2005556..0150d89 100644
--- a/ortc/BUILD.gn
+++ b/ortc/BUILD.gn
@@ -91,7 +91,6 @@
       "../rtc_base:rtc_base_tests_main",
       "../rtc_base:rtc_base_tests_utils",
       "../system_wrappers:metrics_default",
-      "../system_wrappers:runtime_enabled_features_default",
     ]
 
     if (!build_with_chromium && is_clang) {
diff --git a/pc/BUILD.gn b/pc/BUILD.gn
index 58e27c0..27679ac 100644
--- a/pc/BUILD.gn
+++ b/pc/BUILD.gn
@@ -309,7 +309,6 @@
       "../rtc_base:rtc_base_tests_main",
       "../rtc_base:rtc_base_tests_utils",
       "../system_wrappers:metrics_default",
-      "../system_wrappers:runtime_enabled_features_default",
       "../test:test_support",
     ]
 
@@ -496,7 +495,6 @@
       "../rtc_base:rtc_base_tests_main",
       "../rtc_base:rtc_base_tests_utils",
       "../system_wrappers:metrics_default",
-      "../system_wrappers:runtime_enabled_features_default",
       "../test:audio_codec_mocks",
       "../test:test_support",
     ]
diff --git a/sdk/BUILD.gn b/sdk/BUILD.gn
index b587a55..121e47c 100644
--- a/sdk/BUILD.gn
+++ b/sdk/BUILD.gn
@@ -751,7 +751,6 @@
           "../rtc_base:rtc_base_approved",
           "../system_wrappers:field_trial_default",
           "../system_wrappers:metrics_default",
-          "../system_wrappers:runtime_enabled_features_default",
         ]
 
         libs = [
@@ -780,7 +779,6 @@
         ":ui_objc",
         "../system_wrappers:field_trial_default",
         "../system_wrappers:metrics_default",
-        "../system_wrappers:runtime_enabled_features_default",
       ]
     }
 
diff --git a/sdk/android/BUILD.gn b/sdk/android/BUILD.gn
index e484632..fa4a8f9 100644
--- a/sdk/android/BUILD.gn
+++ b/sdk/android/BUILD.gn
@@ -471,7 +471,6 @@
     "../../system_wrappers:field_trial_default",
     "../../system_wrappers:metrics_api",
     "../../system_wrappers:metrics_default",
-    "../../system_wrappers:runtime_enabled_features_default",
   ]
 }
 
diff --git a/system_wrappers/include/runtime_enabled_features.h b/system_wrappers/include/runtime_enabled_features.h
index 9ccbedc..a972cda 100644
--- a/system_wrappers/include/runtime_enabled_features.h
+++ b/system_wrappers/include/runtime_enabled_features.h
@@ -21,12 +21,8 @@
 // TODO(ilnik): Find a more flexible way to use Chrome features.
 // This interface requires manual translation from feature name to
 // Chrome feature class in third_party/webrtc_overrides.
-
 namespace webrtc {
 namespace runtime_enabled_features {
-
-const char kDualStreamModeFeatureName[] = "WebRtcDualStreamMode";
-
 bool IsFeatureEnabled(std::string feature_name);
 
 }  // namespace runtime_enabled_features
diff --git a/system_wrappers/source/runtime_enabled_features_default.cc b/system_wrappers/source/runtime_enabled_features_default.cc
index 31a3ff7..cd0d157 100644
--- a/system_wrappers/source/runtime_enabled_features_default.cc
+++ b/system_wrappers/source/runtime_enabled_features_default.cc
@@ -22,7 +22,7 @@
 namespace runtime_enabled_features {
 
 bool IsFeatureEnabled(std::string feature_name) {
-  if (feature_name == kDualStreamModeFeatureName)
+  if (feature_name == "WebRtcDualStreamMode")
     return flags::FLAG_enable_dual_stream_mode;
   return false;
 }
diff --git a/test/BUILD.gn b/test/BUILD.gn
index d7a2e77..a83e8bb 100644
--- a/test/BUILD.gn
+++ b/test/BUILD.gn
@@ -214,7 +214,6 @@
       ":perf_test",
       "../rtc_base:rtc_base_approved",
       "../system_wrappers:metrics_default",
-      "../system_wrappers:runtime_enabled_features_default",
       "//testing/gmock",
       "//testing/gtest",
     ]
@@ -627,7 +626,6 @@
     "../rtc_base:sequenced_task_checker",
     "../system_wrappers",
     "../system_wrappers:field_trial_api",
-    "../system_wrappers:runtime_enabled_features_api",
     "../video",
     "//testing/gmock",
     "//testing/gtest",
diff --git a/test/fuzzers/BUILD.gn b/test/fuzzers/BUILD.gn
index 90fb62c..0ccabfc 100644
--- a/test/fuzzers/BUILD.gn
+++ b/test/fuzzers/BUILD.gn
@@ -18,7 +18,6 @@
     "../../rtc_base:rtc_base_approved",
     "../../system_wrappers:field_trial_default",
     "../../system_wrappers:metrics_default",
-    "../../system_wrappers:runtime_enabled_features_default",
     "//testing/libfuzzer:libfuzzer_main",
   ]
 }
diff --git a/video/BUILD.gn b/video/BUILD.gn
index 3d2d5e9..8502691 100644
--- a/video/BUILD.gn
+++ b/video/BUILD.gn
@@ -169,7 +169,6 @@
       ":video_quality_test",
       "../rtc_base:rtc_base_approved",
       "../system_wrappers:metrics_default",
-      "../system_wrappers:runtime_enabled_features_default",
       "../test:field_trial",
       "../test:run_test",
       "../test:run_test_interface",
@@ -195,7 +194,6 @@
       ":video_quality_test",
       "../rtc_base:rtc_base_approved",
       "../system_wrappers:metrics_default",
-      "../system_wrappers:runtime_enabled_features_default",
       "../test:field_trial",
       "../test:run_test",
       "../test:run_test_interface",
@@ -219,7 +217,6 @@
       ":video_quality_test",
       "../rtc_base:rtc_base_approved",
       "../system_wrappers:metrics_default",
-      "../system_wrappers:runtime_enabled_features_default",
       "../test:field_trial",
       "../test:run_test",
       "../test:run_test_interface",
@@ -252,7 +249,6 @@
       "../rtc_base:rtc_base_approved",
       "../system_wrappers",
       "../system_wrappers:metrics_default",
-      "../system_wrappers:runtime_enabled_features_default",
       "../test:field_trial",
       "../test:rtp_test_utils",
       "../test:run_test",