Simulate transient error and verify exponential backoff.

chrome/browser/sync/retry_verifier.h

Index: chrome/browser/sync/retry_verifier.h
diff --git a/chrome/browser/sync/retry_verifier.h b/chrome/browser/sync/retry_verifier.h
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+// Copyright (c) 2011 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_SYNC_RETRY_VERIFIER_H_
+#define CHROME_BROWSER_SYNC_RETRY_VERIFIER_H_
+#pragma once
+
+
+#include "base/time.h"
+
+
+namespace browser_sync {
+  namespace sessions {
+    struct SyncSessionSnapshot;
+  }
+}
+
+// The minimum and maximum wait times for a retry. The actual retry would take
+// place somewhere in this range. The algorithm that calculates the retry wait
+// time uses rand functions.
+struct DelayInfo {
+  int64 min_delay;
+  int64 max_delay;
+};
+
+// Class to verify retries take place using the exponential backoff algorithm.
+class RetryVerifier {
+ public:
+  static const int max_retry = 10;
+  RetryVerifier();
+  ~RetryVerifier();
+  int RetryCount() const { return retry_count; }
+  void Initialize(const browser_sync::sessions::SyncSessionSnapshot& snap);
+  bool VerifyRetryInterval(
+      const browser_sync::sessions::SyncSessionSnapshot& snap);
+
+ private:
+  int retry_count;
+  base::Time last_sync_time;
+  DelayInfo delay_table[max_retry];
+};
+
+#endif  // CHROME_BROWSER_SYNC_RETRY_VERIFIER_H_