components/cronet/android/proto/base_feature_overrides.proto

syntax = "proto2";

package org.chromium.net.httpflags;

option java_package = "org.chromium.net.httpflags";
option java_multiple_files = true;
option optimize_for = LITE_RUNTIME;  // crbug/800281

// Describes a set of overrides for `base::Feature` flags.
message BaseFeatureOverrides {
  // Describes the state of a given base::Feature.
  //
  // Note that currently this doesn't support customizing the name of the fake
  // field trial (a.k.a study) and group (a.k.a experiment) that will be
  // associated with the base::Feature. It is highly unlikely you'd need to do
  // this, though.
  message FeatureState {
    // If set, the feature will be overridden to the enabled state (true) or the
    // disabled state (false). If unset, the feature state will not be
    //  overridden.
    optional bool enabled = 1;

    // The set of Feature Params that will be associated with the feature, as
    // key-value pairs. (More specifically: the set of params that will be
    // associated with the "fake" field trial and group that the feature is
    // associated with.)
    //
    // The usual Feature Params APIs will return an empty params map for
    // disabled features. It is possible to work around this limitation, but
    // typical code wouldn't, so you almost certainly want to explicitly enable
    // the feature by setting the `enabled` field above to `true` if you want
    // this field to have any effect.
    //
    // Behind the scenes, feature params are always string-valued, which is why
    // this map is string-valued as well (actually bytes-valued, to hedge
    // against the remote possibility that someone might want to stuff binary or
    // non-UTF-8 data in there). The non-string variants of the
    // base::FeatureParam API (int, float, etc.) are really just convenience
    // string parsers.
    //
    // The base::FeatureParam API will return the param default value if there
    // is no entry for the corresponding param name, OR if the value is the
    // empty string. Crucially, this means it is NOT possible to override a
    // base::FeatureParam to the empty string. This limitation does not apply to
    // lower-level APIs such as base::GetFieldTrialParamsByFeature().
    //
    // If this field is empty, no param map will be associated with the feature.
    // Note that this is subtly different from an empty param map as that
    // affects the return value of low-level APIs such as
    // base::GetFieldTrialParamsByFeature(). The high-level base::FeatureParam
    // API will not surface that difference, though. This proto does not
    // currently provide a way to associate an empty map.
    map<string, bytes> params = 2;
  }

  // The key is the name of the base::Feature.
  map<string, FeatureState> feature_states = 1;
}