Move VariationsParamAssociator to base

base/metrics/field_trial_param_associator.cc

+// Copyright 2016 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_param_associator.h"
+
+#include "base/metrics/field_trial.h"
+
+namespace base {
+
+FieldTrialParamAssociator::FieldTrialParamAssociator() {}
+FieldTrialParamAssociator::~FieldTrialParamAssociator() {}
+
+// static
+FieldTrialParamAssociator* FieldTrialParamAssociator::GetInstance() {
+  return Singleton<FieldTrialParamAssociator,
+                   LeakySingletonTraits<FieldTrialParamAssociator>>::get();
+}
+
+bool FieldTrialParamAssociator::AssociateFieldTrialParams(
+    const std::string& trial_name,
+    const std::string& group_name,
+    const FieldTrialParams& params) {
+  AutoLock scoped_lock(lock_);
+
+  if (FieldTrialList::IsTrialActive(trial_name))
+    return false;
+
+  const FieldTrialKey key(trial_name, group_name);
+  if (ContainsKey(field_trial_params_, key))
+    return false;
+
+  field_trial_params_[key] = params;
+  return true;
+}
+
+bool FieldTrialParamAssociator::GetFieldTrialParams(
+    const std::string& trial_name,
+    FieldTrialParams* params) {
+  AutoLock scoped_lock(lock_);
+
+  const std::string group_name = FieldTrialList::FindFullName(trial_name);
+  const FieldTrialKey key(trial_name, group_name);
+  if (!ContainsKey(field_trial_params_, key))
+    return false;
+
+  *params = field_trial_params_[key];
+  return true;
+}
+
+void FieldTrialParamAssociator::ClearAllParamsForTesting() {
+  AutoLock scoped_lock(lock_);
+  field_trial_params_.clear();
+}
+
+}  // namespace base