Upstream oodles of Chrome for Android code into Chromium.

chrome/browser/android/history_report/usage_reports_buffer_service.h

Index: chrome/browser/android/history_report/usage_reports_buffer_service.h
diff --git a/chrome/browser/android/history_report/usage_reports_buffer_service.h b/chrome/browser/android/history_report/usage_reports_buffer_service.h
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+// Copyright 2015 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_ANDROID_HISTORY_REPORT_USAGE_REPORTS_BUFFER_SERVICE_H_
+#define CHROME_BROWSER_ANDROID_HISTORY_REPORT_USAGE_REPORTS_BUFFER_SERVICE_H_
+
+#include <string>
+#include <vector>
+
+#include "base/memory/scoped_ptr.h"
+#include "base/threading/sequenced_worker_pool.h"
+
+namespace base {
+class FilePath;
+}  // namespace base
+
+namespace history_report {
+
+class UsageReport;
+class UsageReportsBufferBackend;
+
+// This class is intended to be created once and not destroyed until process is
+// killed. |backend_| is assumed to be a long lived pointer.
+class UsageReportsBufferService {
+ public:
+  explicit UsageReportsBufferService(const base::FilePath& dir);
+  ~UsageReportsBufferService();
+
+  // Init buffer. All calls to buffer before it's initialized are ignored. It's
+  // asynchronous.
+  void Init();
+
+  // Add report about page visit to the buffer. It's asynchronous.
+  void AddVisit(const std::string& id, int64 timestamp_ms, bool typed_visit);
+
+  // Get a batch of usage reports of size up to |batch_size|. It's synchronous.
+  scoped_ptr<std::vector<UsageReport> > GetUsageReportsBatch(int32 batch_size);
+
+  // Remove given usage reports from buffer. It's synchronous.
+  void Remove(const std::vector<std::string>& report_ids);
+
+  // Clears buffer by removing all usage reports from it.
+  void Clear();
+
+  // Dumps internal state to string.
+  std::string Dump();
+
+ private:
+  // Token used to serialize buffer operations.
+  base::SequencedWorkerPool::SequenceToken worker_pool_token_;
+  // Non thread safe backend.
+  scoped_ptr<UsageReportsBufferBackend> backend_;
+
+  DISALLOW_COPY_AND_ASSIGN(UsageReportsBufferService);
+};
+
+}  // namespace history_report
+
+#endif  // CHROME_BROWSER_ANDROID_HISTORY_REPORT_USAGE_REPORTS_BUFFER_SERVICE_H_