Test field trial group with startswith rather than equals.

webrtc/modules/rtp_rtcp/source/rtp_sender.cc

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 106 matching lines @@
       capture_time_ms_(0),
       last_timestamp_time_ms_(0),
       media_has_been_sent_(false),
       last_packet_marker_bit_(false),
       csrcs_(),
       rtx_(kRtxOff),
       rtp_overhead_bytes_per_packet_(0),
       retransmission_rate_limiter_(retransmission_rate_limiter),
       overhead_observer_(overhead_observer),
       send_side_bwe_with_overhead_(
-          webrtc::field_trial::FindFullName(
-              "WebRTC-SendSideBwe-WithOverhead") == "Enabled") {
+          webrtc::field_trial::IsEnabled("WebRTC-SendSideBwe-WithOverhead")) {
   // This random initialization is not intended to be cryptographic strong.
   timestamp_offset_ = random_.Rand<uint32_t>();
   // Random start, 16 bits. Can't be 0.
   sequence_number_rtx_ = random_.Rand(1, kMaxInitRtpSeqNumber);
   sequence_number_ = random_.Rand(1, kMaxInitRtpSeqNumber);
 
   // Store FlexFEC packets in the packet history data structure, so they can
   // be found when paced.
   if (flexfec_sender) {
     flexfec_packet_history_.SetStorePacketsStatus(
@@ skipping 1136 matching lines @@
     if (rtp_overhead_bytes_per_packet_ == packet.headers_size()) {
       return;
     }
     rtp_overhead_bytes_per_packet_ = packet.headers_size();
     overhead_bytes_per_packet = rtp_overhead_bytes_per_packet_;
   }
   overhead_observer_->OnOverheadChanged(overhead_bytes_per_packet);
 }
 
 }  // namespace webrtc