Allow BackoffEntry to be serialized and deserialized.

net/base/backoff_entry_serializer.h

Index: net/base/backoff_entry_serializer.h
diff --git a/net/base/backoff_entry_serializer.h b/net/base/backoff_entry_serializer.h
new file mode 100644
index 0000000000000000000000000000000000000000..837265727fb4d4d768a61999df4dd6f192615d8f
--- /dev/null
+++ b/net/base/backoff_entry_serializer.h
@@ -0,0 +1,55 @@
+// 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 NET_BASE_BACKOFF_ENTRY_SERIALIZER_H_
+#define NET_BASE_BACKOFF_ENTRY_SERIALIZER_H_
+
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/time/time.h"
+#include "net/base/backoff_entry.h"
+#include "net/base/net_export.h"
+
+namespace base {
+class Value;
+class TickClock;
+}
+
+namespace net {
+
+// Serialize or deserialize a BackoffEntry, so it can persist beyond the
+// lifetime of the browser.
+class NET_EXPORT BackoffEntrySerializer {
+ public:
+  // Serializes the release time and failure count into a ListValue that can
+  // later be passed to Deserialize to re-create the given BackoffEntry. The
+  // Policy is not serialized, instead callers must pass an identical Policy*
+  // when deserializing. |time_now| should be base::Time::Now(), except for
+  // tests that want to simulate time changes. The release time TimeTicks will
+  // be converted to an absolute timestamp, thus the time will continue counting
+  // down even whilst the device is powered off, and will be partially
+  // vulnerable to changes in the system clock time.
+  static scoped_ptr<base::Value> SerializeToValue(const BackoffEntry& entry,
+                                                  base::Time time_now);
+
+  // Deserializes a ListValue back to a BackoffEntry. |policy| MUST be the same
+  // Policy as the serialized entry had. |clock| may be NULL. Both |policy| and
+  // |clock| (if not NULL) must enclose lifetime of the returned BackoffEntry.
+  // |time_now| should be base::Time::Now(), except for tests that want to
+  // simulate time changes. The absolute timestamp that was serialized will be
+  // converted back to TimeTicks as best as possible. Returns NULL if
+  // deserialization was unsuccessful.
+  static scoped_ptr<BackoffEntry> DeserializeFromValue(
+      const base::Value& serialized,
+      const BackoffEntry::Policy* policy,
+      base::TickClock* clock,
+      base::Time time_now);
+
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(BackoffEntrySerializer);
+};
+
+}  // namespace net
+
+#endif  // NET_BASE_BACKOFF_ENTRY_SERIALIZER_H_