[Sync] Fixing two bugs in the worker revealed by trying to add an encryption integration test.

components/sync/engine_impl/worker_entity_tracker.cc

Index: components/sync/engine_impl/worker_entity_tracker.cc
diff --git a/components/sync/engine_impl/worker_entity_tracker.cc b/components/sync/engine_impl/worker_entity_tracker.cc
index 2b73b20fe1113bf45d33ea8b31466ad6d472b7d7..5e428679e28ff503579135a682268052f0aef1d2 100644
--- a/components/sync/engine_impl/worker_entity_tracker.cc
+++ b/components/sync/engine_impl/worker_entity_tracker.cc
@@ -4,7 +4,7 @@
 
 #include "components/sync/engine_impl/worker_entity_tracker.h"
 
-#include <stdint.h>
+#include <algorithm>
 
 #include "base/logging.h"
 #include "components/sync/base/model_type.h"
@@ -96,6 +96,10 @@ void WorkerEntityTracker::RequestCommit(const CommitRequestData& data) {
     return;
   }
 
+  // There's no conflict; increase base_version_ if there was a commit response
+  // the processor didn't know about.
+  base_version_ = std::max(base_version_, highest_commit_response_version_);
+
   // Otherwise, keep the data associated with this pending commit
   // so it can be committed at the next possible opportunity.
 }