chrome/browser/metrics/variations/variations_registry_syncer_win.h

   1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CHROME_BROWSER_METRICS_VARIATIONS_VARIATIONS_REGISTRY_SYNCER_WIN_H_
   6 #define CHROME_BROWSER_METRICS_VARIATIONS_VARIATIONS_REGISTRY_SYNCER_WIN_H_
   7
   8 #include "base/timer/timer.h"
   9
  10 namespace chrome_variations {
  11
  12 // This class manages synchronizing active VariationIDs with the Google Update
  13 // experiment_labels value in the registry.
  14 class VariationsRegistrySyncer {
  15  public:
  16   VariationsRegistrySyncer();
  17   ~VariationsRegistrySyncer();
  18
  19   // Starts a timer that, when it expires, updates the registry with the current
  20   // Variations associated with Google Update. If the timer is already running,
  21   // calling this just resets the timer.
  22   void RequestRegistrySync();
  23
  24  private:
  25   // Starts the actual synchronization process with the registry. Posts a task
  26   // to do it on the blocking pool to avoid jank.
  27   void StartRegistrySync();
  28
  29   // A timer used to delay the writes to the registry. This is done to optimize
  30   // the case where lazy-loaded features start their field trials some time
  31   // after initial batch of field trials are created, and also to avoid blocking
  32   // the UI thread. The timer effectively allows this class to batch together
  33   // update requests, to avoid reading and writing from the registry too much.
  34   base::OneShotTimer<VariationsRegistrySyncer> timer_;
  35
  36   DISALLOW_COPY_AND_ASSIGN(VariationsRegistrySyncer);
  37 };
  38
  39 }  // namespace chrome_variations
  40
  41 #endif  // CHROME_BROWSER_METRICS_VARIATIONS_VARIATIONS_REGISTRY_SYNCER_WIN_H_