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

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

Index: chrome/browser/sync/test/integration/migration_waiter.cc
diff --git a/chrome/browser/sync/test/integration/migration_waiter.cc b/chrome/browser/sync/test/integration/migration_waiter.cc
index 565b3ccc89112e8062a7ae673f5cbd9ca1a29018..37db9b3009f59adc2e093e286d7ce8f75808a1b2 100644
--- a/chrome/browser/sync/test/integration/migration_waiter.cc
+++ b/chrome/browser/sync/test/integration/migration_waiter.cc
@@ -31,15 +31,6 @@ std::string MigrationWaiter::GetDebugMessage() const {
          ModelTypeSetToString(watcher_->GetMigratedTypes()) + ")";
 }
 
-void MigrationWaiter::Wait() {
-  if (IsExitConditionSatisfied()) {
-    DVLOG(1) << "Skipping wait: " << GetDebugMessage();
-    return;
-  }
-
-  StartBlockingWait();
-}
-
 void MigrationWaiter::OnMigrationStateChange() {
   CheckExitCondition();
 }