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

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

 // Copyright 2016 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/fake_server_match_status_checker.h"
+
 #include "chrome/browser/sync/test/integration/sync_datatype_helper.h"
 #include "chrome/browser/sync/test/integration/sync_test.h"
 
 namespace fake_server {
 
 FakeServerMatchStatusChecker::FakeServerMatchStatusChecker()
     : fake_server_(sync_datatype_helper::test()->GetFakeServer()) {
   DCHECK(fake_server_);
+  fake_server_->AddObserver(this);
 }
 
-void FakeServerMatchStatusChecker::Wait() {
-  DVLOG(1) << "Await: " << GetDebugMessage();
-
-  if (IsExitConditionSatisfied()) {
-    DVLOG(1) << "Await -> Exit before waiting: " << GetDebugMessage();
-    return;
-  }
-
-  fake_server_->AddObserver(this);
-  StartBlockingWait();
+FakeServerMatchStatusChecker::~FakeServerMatchStatusChecker() {
   fake_server_->RemoveObserver(this);
 }
 
 void FakeServerMatchStatusChecker::OnCommit(
     const std::string& committer_id,
     syncer::ModelTypeSet committed_model_types) {
   CheckExitCondition();
 }
 
 fake_server::FakeServer* FakeServerMatchStatusChecker::fake_server() const {
   return fake_server_;
 }
 
 }  // namespace fake_server