sync: Expose sync functionality as functions

sync/sessions/nudge_tracker_unittest.cc

Index: sync/sessions/nudge_tracker_unittest.cc
diff --git a/sync/sessions/nudge_tracker_unittest.cc b/sync/sessions/nudge_tracker_unittest.cc
index 9e6ce99d0c578d3840e2664ee48ee3b11fd8ec03..797e78dee5de0836068870c10a2f59e71a06b1b3 100644
--- a/sync/sessions/nudge_tracker_unittest.cc
+++ b/sync/sessions/nudge_tracker_unittest.cc
@@ -53,6 +53,13 @@ class NudgeTrackerTest : public ::testing::Test {
     nudge_tracker.FillProtoMessage(type, &gu_trigger);
     return gu_trigger.datatype_refresh_nudges();
   }
+
+  void FullySync(NudgeTracker* nudge_tracker) {
+    // We enable invalidations and perform a successful sync cycle so our
+    // invalidations list will be 100% up to date and reliable.
+    nudge_tracker->OnInvalidationsEnabled();
+    nudge_tracker->RecordSuccessfulSyncCycle();
+  }
 };
 
 // Exercise an empty NudgeTracker.
@@ -412,6 +419,5 @@ TEST_F(NudgeTrackerTest, OverlappingThrottleIntervals) {
   EXPECT_TRUE(nudge_tracker.GetThrottledTypes().Empty());
 }
 
-
 }  // namespace sessions
 }  // namespace syncer