mash: Provide a fake chromeos StatisticsProvider in ash

chromeos/system/fake_statistics_provider.h

 // 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 CHROMEOS_SYSTEM_FAKE_STATISTICS_PROVIDER_H_
 #define CHROMEOS_SYSTEM_FAKE_STATISTICS_PROVIDER_H_
 
 #include <map>
 #include <string>
 
 #include "base/macros.h"
+#include "chromeos/chromeos_export.h"
 #include "chromeos/system/statistics_provider.h"
 
 namespace chromeos {
 namespace system {
 
 // A fake StatisticsProvider implementation that is useful in tests.
-class FakeStatisticsProvider : public StatisticsProvider {
+class CHROMEOS_EXPORT FakeStatisticsProvider : public StatisticsProvider {
  public:
   FakeStatisticsProvider();
   ~FakeStatisticsProvider() override;
 
   // StatisticsProvider implementation:
   void StartLoadingMachineStatistics(
       const scoped_refptr<base::TaskRunner>& file_task_runner,
       bool load_oem_manifest) override;
   bool GetMachineStatistic(const std::string& name,
                            std::string* result) override;
   bool GetMachineFlag(const std::string& name, bool* result) override;
   void Shutdown() override;
   bool IsRunningOnVm() override;
 
   void SetMachineStatistic(const std::string& key, const std::string& value);
   void ClearMachineStatistic(const std::string& key);
   void SetMachineFlag(const std::string& key, bool value);
   void ClearMachineFlag(const std::string& key);
 
  private:
   std::map<std::string, std::string> machine_statistics_;
   std::map<std::string, bool> machine_flags_;
 
   DISALLOW_COPY_AND_ASSIGN(FakeStatisticsProvider);
 };
 
 // A convenience subclass that automatically registers itself as the test
 // StatisticsProvider during construction and cleans up at destruction.
-class ScopedFakeStatisticsProvider : public FakeStatisticsProvider {
+class CHROMEOS_EXPORT ScopedFakeStatisticsProvider
+    : public FakeStatisticsProvider {
  public:
   ScopedFakeStatisticsProvider();
   ~ScopedFakeStatisticsProvider() override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ScopedFakeStatisticsProvider);
 };
 
 }  // namespace system
 }  // namespace chromeos
 
 #endif  // CHROMEOS_SYSTEM_FAKE_STATISTICS_PROVIDER_H_