[Sync] Minor refactor around SyncCycle and ModelTypeSet usage.

components/sync/engine_impl/sync_scheduler_impl_unittest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/sync/engine_impl/sync_scheduler_impl.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <vector>
@@ skipping 33 matching lines @@
 
 namespace syncer {
 
 using sync_pb::GetUpdatesCallerInfo;
 
 class MockSyncer : public Syncer {
  public:
   MockSyncer();
   MOCK_METHOD3(NormalSyncShare, bool(ModelTypeSet, NudgeTracker*, SyncCycle*));
   MOCK_METHOD3(ConfigureSyncShare,
-               bool(ModelTypeSet,
+               bool(const ModelTypeSet&,
                     sync_pb::GetUpdatesCallerInfo::GetUpdatesSource,
                     SyncCycle*));
   MOCK_METHOD2(PollSyncShare, bool(ModelTypeSet, SyncCycle*));
 };
 
 MockSyncer::MockSyncer() : Syncer(nullptr) {}
 
 using SyncShareTimes = std::vector<TimeTicks>;
 
 void QuitLoopNow() {
@@ skipping 1689 matching lines @@
 
   // The Exponential backoff should be between previous backoff 1.5 and 2.5
   // times.
   EXPECT_LE(first_blocking_time * 1.5, second_blocking_time);
   EXPECT_GE(first_blocking_time * 2.5, second_blocking_time);
 
   StopSyncScheduler();
 }
 
 }  // namespace syncer