Implement a persistent storage aggregation counter class.

counter_mock.h

Index: counter_mock.h
diff --git a/counter_mock.h b/counter_mock.h
new file mode 100644
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--- /dev/null
+++ b/counter_mock.h
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+// Copyright (c) 2010 The Chromium OS 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 METRICS_COUNTER_MOCK_H_
+#define METRICS_COUNTER_MOCK_H_
+
+#include <string>
+
+#include <gmock/gmock.h>
+
+#include "counter.h"
+
+namespace chromeos_metrics {
+
+class TaggedCounterMock : public TaggedCounterInterface {
+ public:
+  MOCK_METHOD3(Init, void(const char* filename,
+                          Reporter reporter, void* reporter_handle));
+  MOCK_METHOD2(Update, void(int tag, int count));
+  MOCK_METHOD0(Flush, void());
+};
+
+}  // namespace chromeos_metrics
+
+#endif  // METRICS_COUNTER_MOCK_H_