1 // 2 // Copyright (c) 2014 The WebRTC project authors. All Rights Reserved. 3 // 4 // Use of this source code is governed by a BSD-style license 5 // that can be found in the LICENSE file in the root of the source 6 // tree. An additional intellectual property rights grant can be found 7 // in the file PATENTS. All contributing project authors may 8 // be found in the AUTHORS file in the root of the source tree. 9 // 10 11 #ifndef WEBRTC_SYSTEM_WRAPPERS_INTERFACE_FIELD_TRIAL_H_ 12 #define WEBRTC_SYSTEM_WRAPPERS_INTERFACE_FIELD_TRIAL_H_ 13 14 #include <string> 15 16 #include "webrtc/common_types.h" 17 18 // Field trials allow webrtc clients (such as Chrome) to turn on feature code 19 // in binaries out in the field and gather information with that. 20 // 21 // WebRTC clients MUST provide an implementation of: 22 // 23 // std::string webrtc::field_trial::FindFullName(const std::string& trial). 24 // 25 // Or link with a default one provided in: 26 // 27 // system_wrappers/source/system_wrappers.gyp:field_trial_default 28 // 29 // 30 // They are designed to wire up directly to chrome field trials and to speed up 31 // developers by reducing the need to wire APIs to control whether a feature is 32 // on/off. E.g. to experiment with a new method that could lead to a different 33 // trade-off between CPU/bandwidth: 34 // 35 // 1 - Develop the feature with default behaviour off: 36 // 37 // if (FieldTrial::FindFullName("WebRTCExperimenMethod2") == "Enabled") 38 // method2(); 39 // else 40 // method1(); 41 // 42 // 2 - Once the changes are rolled to chrome, the new code path can be 43 // controlled as normal chrome field trials. 44 // 45 // 3 - Evaluate the new feature and clean the code paths. 46 // 47 // Notes: 48 // - NOT every feature is a candidate to be controlled by this mechanism as 49 // it may require negotation between involved parties (e.g. SDP). 50 // 51 // TODO(andresp): since chrome --force-fieldtrials does not marks the trial 52 // as active it does not gets propaged to renderer process. For now one 53 // needs to push a config with start_active:true or run a local finch 54 // server. 55 // 56 // TODO(andresp): find out how to get bots to run tests with trials enabled. 57 58 namespace webrtc { 59 namespace field_trial { 60 61 // Returns the group name chosen for the named trial, or the empty string 62 // if the trial does not exists. 63 // 64 // Note: To keep things tidy append all the trial names with WebRTC. 65 std::string FindFullName(const std::string& name); 66 67 } // namespace field_trial 68 } // namespace webrtc 69 70 #endif // WEBRTC_SYSTEM_WRAPPERS_INTERFACE_FIELD_TRIAL_H_ 71
