[Sync] Refactoring of sync integration test checkers to remove boilerplate await methods.

chrome/browser/sync/test/integration/quiesce_status_change_checker.h

 // Copyright 2014 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.
 
 #ifndef CHROME_BROWSER_SYNC_TEST_INTEGRATION_QUIESCE_STATUS_CHANGE_CHECKER_H_
 #define CHROME_BROWSER_SYNC_TEST_INTEGRATION_QUIESCE_STATUS_CHANGE_CHECKER_H_
 
+#include <string>
 #include <vector>
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/memory/scoped_vector.h"
 #include "base/time/time.h"
 #include "chrome/browser/sync/test/integration/status_change_checker.h"
 
 class ProgressMarkerWatcher;
 
@@ skipping 12 matching lines @@
 // precisely the wrong time, we could end up seeing stale snapshot state
 // (crbug.com/95742), which would make us think that the client has finished
 // syncing when it hasn't.  In practice, this race is rare enough that it
 // doesn't cause test failures.
 class QuiesceStatusChangeChecker : public StatusChangeChecker {
  public:
   explicit QuiesceStatusChangeChecker(
       std::vector<browser_sync::ProfileSyncService*> services);
   ~QuiesceStatusChangeChecker() override;
 
-  // Blocks until all clients have quiesced or we time out.
-  void Wait();
-
   // A callback function for some helper objects.
   void OnServiceStateChanged(browser_sync::ProfileSyncService* service);
 
   // Implementation of StatusChangeChecker.
   bool IsExitConditionSatisfied() override;
   std::string GetDebugMessage() const override;
 
  private:
   std::vector<browser_sync::ProfileSyncService*> services_;
   ScopedVector<ProgressMarkerWatcher> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(QuiesceStatusChangeChecker);
 };
 
 #endif  // CHROME_BROWSER_SYNC_TEST_INTEGRATION_QUIESCE_STATUS_CHANGE_CHECKER_H_