Add a counter to calculate the total size of site data.

chrome/browser/browsing_data/site_data_counter.h

Index: chrome/browser/browsing_data/site_data_counter.h
diff --git a/chrome/browser/browsing_data/site_data_counter.h b/chrome/browser/browsing_data/site_data_counter.h
new file mode 100644
index 0000000000000000000000000000000000000000..a685b889f8b4de5a699041dc09aab97e6f51b49f
--- /dev/null
+++ b/chrome/browser/browsing_data/site_data_counter.h
@@ -0,0 +1,39 @@
+// 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_BROWSER_BROWSING_DATA_SITE_DATA_COUNTER_H_
+#define CHROME_BROWSER_BROWSING_DATA_SITE_DATA_COUNTER_H_
+
+#include <stdint.h>
+
+#include <memory>
+#include <string>
+
+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "chrome/browser/browsing_data/browsing_data_counter.h"
+#include "chrome/browser/browsing_data/site_data_size_collector.h"
+
+class SiteDataCounter: public BrowsingDataCounter {
+ public:
+  SiteDataCounter();
+  ~SiteDataCounter() override;
+
+  // BrowsingDataCounter:
+  const std::string& GetPrefName() const override;
+
+ private:
+  // BrowsingDataCounter:
+  void Count() override;
+
+  void OnSiteDataSizeFetched(int64_t size);
+
+  const std::string pref_name_;
+  std::unique_ptr<SiteDataSizeCollector> collector_;
+  base::WeakPtrFactory<SiteDataCounter> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(SiteDataCounter);
+};
+
+#endif  // CHROME_BROWSER_BROWSING_DATA_SITE_DATA_COUNTER_H_