Rename all of experiments_helper to variations_helper, including files, namespaces, and various fun…

chrome/common/metrics/experiments_helper.h

-// Copyright (c) 2012 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.
-
-#ifndef CHROME_COMMON_METRICS_EXPERIMENTS_HELPER_H_
-#define CHROME_COMMON_METRICS_EXPERIMENTS_HELPER_H_
-
-#include <string>
-#include <vector>
-
-#include "base/metrics/field_trial.h"
-#include "base/string16.h"
-#include "chrome/common/metrics/variation_ids.h"
-
-// This namespace provides various helpers that extend the functionality around
-// base::FieldTrial.
-//
-// This includes a simple API used to handle getting and setting
-// data related to Google-specific experiments in the browser. This is meant to
-// be an extension to the base::FieldTrial for Google-specific functionality.
-//
-// These calls are meant to be made directly after appending all your groups to
-// a FieldTrial (for associating IDs) and any time after the group selection has
-// been done (for retrieving IDs).
-//
-// Typical usage looks like this:
-//
-// // Set up your trial and groups as usual.
-// FieldTrial* trial = FieldTrialList::FactoryGetFieldTrial(
-//     "trial", 1000, "default", 2012, 12, 31, NULL);
-// const int kHighMemGroup = trial->AppendGroup("HighMem", 20);
-// const int kLowMemGroup = trial->AppendGroup("LowMem", 20);
-// // All groups are now created. We want to associate
-// // chrome_variation::VariationIDs with them, so do that now.
-// AssociateGoogleVariationID("trial", "default", chrome_variations::kValueA);
-// AssociateGoogleVariationID("trial", "HighMem", chrome_variations::kValueB);
-// AssociateGoogleVariationID("trial", "LowMem",  chrome_variations::kValueC);
-//
-// // Elsewhere, we are interested in retrieving the VariationID associated
-// // with |trial|.
-// chrome_variations::VariationID id =
-//     GetGoogleVariationID(trial->name(), trial->group_name());
-// // Do stuff with |id|...
-//
-// The AssociateGoogleVariationID and GetGoogleVariationID API methods are
-// thread safe.
-
-namespace experiments_helper {
-
-// The Unique ID of a trial and its selected group, where the name and group
-// identifiers are hashes of the trial and group name strings.
-struct SelectedGroupId {
-  uint32 name;
-  uint32 group;
-};
-
-// We need to supply a Compare class for templates since SelectedGroupId is a
-// user-defined type.
-struct SelectedGroupIdCompare {
-  bool operator() (const SelectedGroupId& lhs,
-                   const SelectedGroupId& rhs) const {
-    // The group and name fields are just SHA-1 Hashes, so we just need to treat
-    // them as IDs and do a less-than comparison. We test group first, since
-    // name is more likely to collide.
-    if (lhs.group != rhs.group)
-      return lhs.group < rhs.group;
-    return lhs.name < rhs.name;
-  }
-};
-
-// Fills the supplied vector |name_group_ids| (which must be empty when called)
-// with unique SelectedGroupIds for each Field Trial that has a chosen group.
-// Field Trials for which a group has not been chosen yet are NOT returned in
-// this list.
-void GetFieldTrialSelectedGroupIds(
-    std::vector<SelectedGroupId>* name_group_ids);
-
-// Associate a chrome_variations::VariationID value with a FieldTrial group. If
-// an id was previously set for |trial_name| and |group_name|, this does
-// nothing. The group is denoted by |trial_name| and |group_name|. This must be
-// called whenever you prepare a FieldTrial (create the trial and append groups)
-// that needs to have a chrome_variations::VariationID associated with it so
-// Google servers can recognize the FieldTrial.
-void AssociateGoogleVariationID(const std::string& trial_name,
-                                const std::string& group_name,
-                                chrome_variations::VariationID id);
-
-// As above, but overwrites any previously set id.
-void AssociateGoogleVariationIDForce(const std::string& trial_name,
-                                     const std::string& group_name,
-                                     chrome_variations::VariationID id);
-
-// Retrieve the chrome_variations::VariationID associated with a FieldTrial
-// group. The group is denoted by |trial_name| and |group_name|. This will
-// return chrome_variations::kEmptyID if there is currently no associated ID
-// for the named group. This API can be nicely combined with
-// FieldTrial::GetFieldTrialSelectedGroupIds to enumerate the
-// variation IDs for all active FieldTrial groups.
-chrome_variations::VariationID GetGoogleVariationID(
-    const std::string& trial_name,
-    const std::string& group_name);
-
-// Generates experiment chunks from |experiment_strings| that are suitable for
-// crash reporting.
-void GenerateExperimentChunks(const std::vector<string16>& experiment_strings,
-                              std::vector<string16>* chunks);
-
-// Get the current set of chosen FieldTrial groups (aka experiments) and send
-// them to the child process logging module so it can save it for crash dumps.
-void SetChildProcessLoggingExperimentList();
-
-}  // namespace experiments_helper
-
-// Expose some functions for testing. These functions just wrap functionality
-// that is implemented above.
-namespace testing {
-
-void TestGetFieldTrialSelectedGroupIdsForSelectedGroups(
-    const base::FieldTrial::SelectedGroups& selected_groups,
-    std::vector<experiments_helper::SelectedGroupId>* name_group_ids);
-
-uint32 TestHashName(const std::string& name);
-
-}  // namespace testing
-
-#endif  // CHROME_COMMON_METRICS_EXPERIMENTS_HELPER_H_