[Sync] Add ClearServerData support to Sync Scheduler

sync/engine/syncer.h

Index: sync/engine/syncer.h
diff --git a/sync/engine/syncer.h b/sync/engine/syncer.h
index e473bae86381349629d1028ee75c92fce8e898a9..f68ba023ff9ac9ebaf73c1cdd0d12cc076e7457a 100644
--- a/sync/engine/syncer.h
+++ b/sync/engine/syncer.h
@@ -78,6 +78,11 @@ class SYNC_EXPORT_PRIVATE Syncer {
   virtual bool PollSyncShare(ModelTypeSet request_types,
                              sessions::SyncSession* session);
 
+  // Posts a ClearServerData command.
+  // Returns: false if an error occurred and retries shoudl backoff, true

[pavely, 2015/07/27 19:45:05]

shoudl => should

[maniscalco, 2015/07/27 20:38:12]

Good catch.  Fixed.

+  // otherwise.
+  virtual bool PostClearServerData(sessions::SyncSession* session);
+
  private:
   friend class SyncerTest;
   FRIEND_TEST_ALL_PREFIXES(SyncerTest, NameClashWithResolver);