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// 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.
#include <string>
// Field trials allow webrtc clients (such as Chrome) to turn on feature code
// in binaries out in the field and gather information with that.
// WebRTC clients MUST provide an implementation of:
// std::string webrtc::field_trial::FindFullName(const std::string& trial).
// Or link with a default one provided in:
// system_wrappers/system_wrappers.gyp:field_trial_default
// They are designed to wire up directly to chrome field trials and to speed up
// developers by reducing the need to wire APIs to control whether a feature is
// on/off. E.g. to experiment with a new method that could lead to a different
// trade-off between CPU/bandwidth:
// 1 - Develop the feature with default behaviour off:
// if (FieldTrial::FindFullName("WebRTCExperimenMethod2") == "Enabled")
// method2();
// else
// method1();
// 2 - Once the changes are rolled to chrome, the new code path can be
// controlled as normal chrome field trials.
// 3 - Evaluate the new feature and clean the code paths.
// Notes:
// - NOT every feature is a candidate to be controlled by this mechanism as
// it may require negotation between involved parties (e.g. SDP).
// TODO(andresp): since chrome --force-fieldtrials does not marks the trial
// as active it does not gets propaged to renderer process. For now one
// needs to push a config with start_active:true or run a local finch
// server.
// TODO(andresp): find out how to get bots to run tests with trials enabled.
namespace webrtc {
namespace field_trial {
// Returns the group name chosen for the named trial, or the empty string
// if the trial does not exists.
// Note: To keep things tidy append all the trial names with WebRTC.
std::string FindFullName(const std::string& name);
} // namespace field_trial
} // namespace webrtc