sync: Refactor per-datatype throttling

sync/sessions/sync_session_context.h

Index: sync/sessions/sync_session_context.h
diff --git a/sync/sessions/sync_session_context.h b/sync/sessions/sync_session_context.h
index b1fc2971bc1657a65a07c52cb2ad9317764f933d..ebde3f3c9a6f062843c1cf7b8669fddba2a72f03 100644
--- a/sync/sessions/sync_session_context.h
+++ b/sync/sessions/sync_session_context.h
@@ -23,7 +23,6 @@
 #include <string>
 #include <vector>
 
-#include "base/gtest_prod_util.h"
 #include "base/time.h"
 #include "sync/engine/sync_engine_event.h"
 #include "sync/engine/syncer_types.h"
@@ -40,6 +39,7 @@ namespace browser_sync {
 class ConflictResolver;
 class ExtensionsActivityMonitor;
 class ServerConnectionManager;
+class ThrottledDataTypeTracker;
 
 // Default number of items a client can commit in a single message.
 static const int kDefaultMaxCommitBatchSize = 25;
@@ -55,13 +55,11 @@ class SyncSessionContext {
                      const ModelSafeRoutingInfo& model_safe_routing_info,
                      const std::vector<ModelSafeWorker*>& workers,
                      ExtensionsActivityMonitor* extensions_activity_monitor,
+                     ThrottledDataTypeTracker* throttled_data_type_tracker,
                      const std::vector<SyncEngineEventListener*>& listeners,
                      DebugInfoGetter* debug_info_getter,
                      browser_sync::TrafficRecorder* traffic_recorder);
-
-  // Empty constructor for unit tests.
-  SyncSessionContext();
-  virtual ~SyncSessionContext();
+  ~SyncSessionContext();
 
   ConflictResolver* resolver() { return resolver_; }
   ServerConnectionManager* connection_manager() {
@@ -87,6 +85,10 @@ class SyncSessionContext {
     return extensions_activity_monitor_;
   }
 
+  ThrottledDataTypeTracker* throttled_data_type_tracker() {
+    return throttled_data_type_tracker_;
+  }
+
   DebugInfoGetter* debug_info_getter() {
     return debug_info_getter_;
   }
@@ -122,29 +124,11 @@ class SyncSessionContext {
                       OnSyncEngineEvent(event));
   }
 
-  // This is virtual for unit tests.
-  virtual void SetUnthrottleTime(syncable::ModelTypeSet types,
-                                 const base::TimeTicks& time);
-
-  // This prunes the |unthrottle_time_| map based on the |time| passed in. This
-  // is called by syncer at the SYNCER_BEGIN stage.
-  void PruneUnthrottledTypes(const base::TimeTicks& time);
-
-  // This returns the list of currently throttled types. Unless server returns
-  // new throttled types this will remain constant through out the sync cycle.
-  syncable::ModelTypeSet GetThrottledTypes() const;
-
   browser_sync::TrafficRecorder* traffic_recorder() {
     return traffic_recorder_;
   }
 
  private:
-  typedef std::map<syncable::ModelType, base::TimeTicks> UnthrottleTimes;
-
-  FRIEND_TEST_ALL_PREFIXES(SyncSessionContextTest, AddUnthrottleTimeTest);
-  FRIEND_TEST_ALL_PREFIXES(SyncSessionContextTest,
-                           GetCurrentlyThrottledTypesTest);
-
   // Rather than force clients to set and null-out various context members, we
   // extend our encapsulation boundary to scoped helpers that take care of this
   // once they are allocated. See definitions of these below.
@@ -184,14 +168,12 @@ class SyncSessionContext {
   // by the user.
   ModelSafeRoutingInfo previous_session_routing_info_;
 
+  ThrottledDataTypeTracker* throttled_data_type_tracker_;
+
   // We use this to get debug info to send to the server for debugging
   // client behavior on server side.
   DebugInfoGetter* const debug_info_getter_;
 
-  // This is a map from throttled data types to the time at which they can be
-  // unthrottled.
-  UnthrottleTimes unthrottle_times_;
-
   browser_sync::TrafficRecorder* traffic_recorder_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncSessionContext);