Test field trial group with startswith rather than equals.

webrtc/media/engine/simulcast.cc

 /*
  *  Copyright (c) 2014 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 281 matching lines @@
     return false;
   }
 
   config->tl0_bitrate_kbps = tl0_bitrate;
   config->tl1_bitrate_kbps = tl1_bitrate;
 
   return true;
 }
 
 bool UseSimulcastScreenshare() {
-  return webrtc::field_trial::FindFullName(
-             kSimulcastScreenshareFieldTrialName) == "Enabled";
+  return webrtc::field_trial::IsEnabled(kSimulcastScreenshareFieldTrialName);
 }
 
 }  // namespace cricket