Store field trial parameters in shared memory

base/metrics/field_trial.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.
 
 // FieldTrial is a class for handling details of statistical experiments
 // performed by actual users in the field (i.e., in a shipped or beta product).
 // All code is called exclusively on the UI thread currently.
 //
 // The simplest example is an experiment to see whether one of two options
 // produces "better" results across our user population.  In that scenario, UMA
@@ skipping 51 matching lines @@
 #include <set>
 #include <string>
 #include <vector>
 
 #include "base/base_export.h"
 #include "base/command_line.h"
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/shared_memory.h"
+#include "base/metrics/field_trial_param_associator.h"
 #include "base/metrics/persistent_memory_allocator.h"
 #include "base/observer_list_threadsafe.h"
 #include "base/process/launch.h"
 #include "base/strings/string_piece.h"
 #include "base/synchronization/lock.h"
 #include "base/time/time.h"
 
 namespace base {
 
 class FieldTrialList;
@@ skipping 339 matching lines @@
   // Returns the group number chosen for the named trial, or
   // FieldTrial::kNotFinalized if the trial does not exist.
   static int FindValue(const std::string& trial_name);
 
   // Returns the group name chosen for the named trial, or the empty string if
   // the trial does not exist. The first call of this function on a given field
   // trial will mark it as active, so that its state will be reported with usage
   // metrics, crashes, etc.
   static std::string FindFullName(const std::string& trial_name);
 
+  static bool FindParams(const std::string& trial_name,
+                         FieldTrialParamAssociator::FieldTrialParams* params);
+
   // Returns true if the named trial has been registered.
   static bool TrialExists(const std::string& trial_name);
 
   // Returns true if the named trial exists and has been activated.
   static bool IsTrialActive(const std::string& trial_name);
 
   // Creates a persistent representation of active FieldTrial instances for
   // resurrection in another process. This allows randomization to be done in
   // one process, and secondary processes can be synchronized on the result.
   // The resulting string contains the name and group name pairs of all
@@ skipping 91 matching lines @@
   // Notify all observers that a group has been finalized for |field_trial|.
   static void NotifyFieldTrialGroupSelection(FieldTrial* field_trial);
 
   // Return the number of active field trials.
   static size_t GetFieldTrialCount();
 
  private:
   // Allow tests to access our innards for testing purposes.
   FRIEND_TEST_ALL_PREFIXES(FieldTrialListTest, InstantiateAllocator);
   FRIEND_TEST_ALL_PREFIXES(FieldTrialListTest, AddTrialsToAllocator);
+  FRIEND_TEST_ALL_PREFIXES(FieldTrialListTest, AssociateFieldTrialParams);
 
   // Expects a mapped piece of shared memory |shm| that was created from the
   // browser process's field_trial_allocator and shared via the command line.
   // This function recreates the allocator, iterates through all the field
   // trials in it, and creates them via CreateFieldTrial().
   static void CreateTrialsFromSharedMemory(
       std::unique_ptr<base::SharedMemory> shm);
 
   // Instantiate the field trial allocator, add all existing field trials to it,
   // and duplicates its handle to a read-only handle, which gets stored in
@@ skipping 56 matching lines @@
   // AppendFieldTrialHandleIfNeeded().
   HANDLE readonly_allocator_handle_ = nullptr;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(FieldTrialList);
 };
 
 }  // namespace base
 
 #endif  // BASE_METRICS_FIELD_TRIAL_H_