text: // Copyright 2014 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 COMPONENTS_METRICS_CLONED_INSTALL_DETECTOR_H_
  #define COMPONENTS_METRICS_CLONED_INSTALL_DETECTOR_H_
  
  #include "base/gtest_prod_util.h"
  #include "base/macros.h"
  #include "base/memory/ref_counted.h"
  #include "base/memory/weak_ptr.h"
  
  class PrefRegistrySimple;
  class PrefService;
  
  namespace base {
  class SingleThreadTaskRunner;
  }
  
  namespace metrics {
  
  class MachineIdProvider;
  
  // A class for detecting if an install is cloned. It does this by detecting
  // when the hardware running Chrome changes.
  class ClonedInstallDetector {
   public:
    explicit ClonedInstallDetector(MachineIdProvider* raw_id_provider);
    virtual ~ClonedInstallDetector();
  
    // Posts a task to |task_runner| to generate a machine ID and store it to a
    // local state pref. If the newly generated ID is different than the
    // previously stored one, then the install is considered cloned. The ID is a
    // 24-bit value based off of machine characteristics. This value should never
    // be sent over the network.
    // TODO(jwd): Implement change detection.
    void CheckForClonedInstall(
        PrefService* local_state,
        scoped_refptr<base::SingleThreadTaskRunner> task_runner);
  
    static void RegisterPrefs(PrefRegistrySimple* registry);
  
   private:
    FRIEND_TEST_ALL_PREFIXES(ClonedInstallDetectorTest, SaveId);
    FRIEND_TEST_ALL_PREFIXES(ClonedInstallDetectorTest, DetectClone);
  
    // Converts raw_id into a 24-bit hash and stores the hash in |local_state|.
    // |raw_id| is not a const ref because it's passed from a cross-thread post
    // task.
    void SaveMachineId(PrefService* local_state, const std::string& raw_id);
  
    scoped_refptr<MachineIdProvider> raw_id_provider_;
    base::WeakPtrFactory<ClonedInstallDetector> weak_ptr_factory_;
  
    DISALLOW_COPY_AND_ASSIGN(ClonedInstallDetector);
  };
  
  }  // namespace metrics
  
  #endif  // COMPONENTS_METRICS_CLONED_INSTALL_DETECTOR_H_
  