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

chrome/browser/sync/test/integration/multi_client_status_change_checker.cc

 // 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.
 
 #include "chrome/browser/sync/test/integration/multi_client_status_change_checker.h"
 
 #include "base/logging.h"
 #include "base/scoped_observer.h"
 #include "components/browser_sync/profile_sync_service.h"
 
 MultiClientStatusChangeChecker::MultiClientStatusChangeChecker(
     std::vector<browser_sync::ProfileSyncService*> services)
-    : services_(services) {}
+    : services_(services), scoped_observer_(this) {
+  for (browser_sync::ProfileSyncService* service : services) {
+    scoped_observer_.Add(service);
+  }
+}
 
 MultiClientStatusChangeChecker::~MultiClientStatusChangeChecker() {}
 
-void MultiClientStatusChangeChecker::Wait() {
-  DVLOG(1) << "Await: " << GetDebugMessage();
-
-  if (IsExitConditionSatisfied()) {
-    DVLOG(1) << "Await -> Exit before waiting: " << GetDebugMessage();
-    return;
-  }
-
-  ScopedObserver<browser_sync::ProfileSyncService,
-                 MultiClientStatusChangeChecker>
-      obs(this);
-  for (std::vector<browser_sync::ProfileSyncService*>::iterator it =
-           services_.begin();
-       it != services_.end(); ++it) {
-    obs.Add(*it);
-  }
-
-  StartBlockingWait();
-}
-
 void MultiClientStatusChangeChecker::OnStateChanged() {
   CheckExitCondition();
 }