Rearrange dependency to enable adding finch experiment in webrtc

third_party/libjingle/overrides/field_trial.cc

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/metrics/field_trial.h"
+
+// Define webrtc::field_trial::FindFullName to provide webrtc with a field trial
+// implementation.
+namespace webrtc {
+namespace field_trial {
+std::string FindFullName(const std::string& trial_name) {
+  return base::FieldTrialList::FindFullName(trial_name);
+}
+}  // namespace field_trial
+}  // namespace webrtc