Field trial synchronization to PPAPI process.

chrome/common/variations/child_process_field_trial_syncer.h

-// 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.
-
-#ifndef CHROME_COMMON_VARIATIONS_CHILD_PROCESS_FIELD_TRIAL_SYNCER_H_
-#define CHROME_COMMON_VARIATIONS_CHILD_PROCESS_FIELD_TRIAL_SYNCER_H_
-
-#include <string>
-
-#include "base/macros.h"
-#include "base/metrics/field_trial.h"
-
-namespace base {
-class CommandLine;
-}
-
-namespace chrome_variations {
-
-// ChildProcessFieldTrialSyncer is a utility class that's responsible for
-// syncing the "activated" state of field trials between browser and child
-// processes. Specifically, when a field trial is activated in the browser, it
-// also activates it in the child process and when a field trial is activated
-// in the child process, it notifies the browser process to activate it.
-class ChildProcessFieldTrialSyncer {
- public:
-  // ChildProcessFieldTrialSyncer constructor taking an externally owned
-  // |observer| param that's responsible for sending IPCs to the browser process
-  // when a trial is activated. The |observer| must outlive this object.
-  explicit ChildProcessFieldTrialSyncer(
-      base::FieldTrialList::Observer* observer);
-  ~ChildProcessFieldTrialSyncer();
-
-  // Initializes field trial state change observation and notifies the browser
-  // of any field trials that might have already been activated.
-  void InitFieldTrialObserving(const base::CommandLine& command_line);
-
-  // Handler for messages from the browser process notifying the child process
-  // that a field trial was activated.
-  void OnSetFieldTrialGroup(const std::string& trial_name,
-                            const std::string& group_name);
-
- private:
-  base::FieldTrialList::Observer* const observer_;
-
-  DISALLOW_COPY_AND_ASSIGN(ChildProcessFieldTrialSyncer);
-};
-
-}  // namespace chrome_variations
-
-#endif  // CHROME_COMMON_VARIATIONS_CHILD_PROCESS_FIELD_TRIAL_SYNCER_H_