Client-side changes to support retry GU.

sync/sessions/nudge_tracker.h

Index: sync/sessions/nudge_tracker.h
diff --git a/sync/sessions/nudge_tracker.h b/sync/sessions/nudge_tracker.h
index fcd015034101312d6e71822ee7a772bbbb0af278..35de311a33a82ec7d8a9e0695dbcd9506decadfe 100644
--- a/sync/sessions/nudge_tracker.h
+++ b/sync/sessions/nudge_tracker.h
@@ -11,6 +11,7 @@
 #include <map>
 
 #include "base/compiler_specific.h"
+#include "base/time/clock.h"
 #include "sync/base/sync_export.h"
 #include "sync/internal_api/public/base/model_type.h"
 #include "sync/protocol/sync.pb.h"
@@ -26,7 +27,8 @@ class SYNC_EXPORT_PRIVATE NudgeTracker {
  public:
   static size_t kDefaultMaxPayloadsPerType;
 
-  NudgeTracker();
+  // Takes the ownership of |clock|.
+  explicit NudgeTracker(base::Clock* clock);
   ~NudgeTracker();
 
   // Returns true if there is a good reason for performing a sync cycle.
@@ -38,6 +40,9 @@ class SYNC_EXPORT_PRIVATE NudgeTracker {
   // request as part of the next sync cycle.
   bool IsGetUpdatesRequired() const;
 
+  // Return true if should perform a sync cycle for GU retry.
+  bool IsRetryRequired() const;
+
   // Tells this class that all required update fetching and committing has
   // completed successfully.
   void RecordSuccessfulSyncCycle();
@@ -105,9 +110,15 @@ class SYNC_EXPORT_PRIVATE NudgeTracker {
   // Adjusts the number of hints that can be stored locally.
   void SetHintBufferSize(size_t size);
 
+  void set_next_retry_time(base::Time next_retry_time) {
+    next_retry_time_ = next_retry_time;
+  }
+
  private:
   typedef std::map<ModelType, DataTypeTracker> TypeTrackerMap;
 
+  scoped_ptr<base::Clock> clock_;
+
   TypeTrackerMap type_trackers_;
 
   // Merged updates source.  This should be obsolete, but the server still
@@ -130,6 +141,11 @@ class SYNC_EXPORT_PRIVATE NudgeTracker {
 
   size_t num_payloads_per_type_;
 
+  base::Time last_successful_sync_time_;
+
+  // A retry GU should be issued after this time.
+  base::Time next_retry_time_;
+
   DISALLOW_COPY_AND_ASSIGN(NudgeTracker);
 };