Allow BackoffEntry to be serialized and deserialized.

net/base/backoff_entry.h

Index: net/base/backoff_entry.h
diff --git a/net/base/backoff_entry.h b/net/base/backoff_entry.h
index dbc7488b7a4bd8005b5d699da8158d3a5459685c..be9d510474e9bd7bb0988b114ebee4cb93f6fad8 100644
--- a/net/base/backoff_entry.h
+++ b/net/base/backoff_entry.h
@@ -5,6 +5,7 @@
 #ifndef NET_BASE_BACKOFF_ENTRY_H_
 #define NET_BASE_BACKOFF_ENTRY_H_
 
+#include "base/macros.h"
 #include "base/threading/non_thread_safe.h"
 #include "base/time/time.h"
 #include "net/base/net_export.h"
@@ -22,7 +23,8 @@ namespace net {
 // intended for reuse in various networking scenarios.
 class NET_EXPORT BackoffEntry : NON_EXPORTED_BASE(public base::NonThreadSafe) {
  public:
-  // The set of parameters that define a back-off policy.
+  // The set of parameters that define a back-off policy. When modifying this,
+  // increment SERIALIZATION_VERSION_NUMBER in backoff_entry_serializer.cc.
   struct Policy {
     // Number of initial errors (in sequence) to ignore before applying
     // exponential back-off rules.
@@ -80,9 +82,15 @@ class NET_EXPORT BackoffEntry : NON_EXPORTED_BASE(public base::NonThreadSafe) {
   // state) will no longer reject requests.
   base::TimeTicks GetReleaseTime() const;
 
-  // Returns the time until a request can be sent.
+  // Returns the time until a request can be sent (will be zero if the release
+  // time is in the past).
   base::TimeDelta GetTimeUntilRelease() const;
 
+  // Converts |backoff_duration| to a release time, by adding it to
+  // GetTimeTicksNow(), limited by maximum_backoff_ms.
+  base::TimeTicks BackoffDurationToReleaseTime(
+      base::TimeDelta backoff_duration) const;
+
   // Causes this object reject requests until the specified absolute time.
   // This can be used to e.g. implement support for a Retry-After header.
   void SetCustomReleaseTime(const base::TimeTicks& release_time);
@@ -98,6 +106,9 @@ class NET_EXPORT BackoffEntry : NON_EXPORTED_BASE(public base::NonThreadSafe) {
   // Returns the failure count for this entry.
   int failure_count() const { return failure_count_; }
 
+  // Returns the TickClock passed in to the constructor. May be NULL.
+  base::TickClock* tick_clock() const { return clock_; }
+
  private:
   // Calculates when requests should again be allowed through.
   base::TimeTicks CalculateReleaseTime() const;