Test field trial group with startswith rather than equals.

webrtc/modules/congestion_controller/transport_feedback_adapter.cc

Index: webrtc/modules/congestion_controller/transport_feedback_adapter.cc
diff --git a/webrtc/modules/congestion_controller/transport_feedback_adapter.cc b/webrtc/modules/congestion_controller/transport_feedback_adapter.cc
index fa27cc0b18ff7c054bfc0656bd14b2c0d9a16d5a..97657d4c3fb3e88e9ab78dc7c6be2a0b126c3875 100644
--- a/webrtc/modules/congestion_controller/transport_feedback_adapter.cc
+++ b/webrtc/modules/congestion_controller/transport_feedback_adapter.cc
@@ -45,9 +45,8 @@ TransportFeedbackAdapter::TransportFeedbackAdapter(
     RtcEventLog* event_log,
     Clock* clock,
     BitrateController* bitrate_controller)
-    : send_side_bwe_with_overhead_(webrtc::field_trial::FindFullName(
-                                       "WebRTC-SendSideBwe-WithOverhead") ==
-                                   "Enabled"),
+    : send_side_bwe_with_overhead_(
+          webrtc::field_trial::IsEnabled("WebRTC-SendSideBwe-WithOverhead")),
       transport_overhead_bytes_per_packet_(0),
       send_time_history_(clock, kSendTimeHistoryWindowMs),
       event_log_(event_log),