sync: Refactor migration integration tests

chrome/browser/sync/test/integration/migration_waiter.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/migration_waiter.h"
+
+#include "base/logging.h"
+#include "chrome/browser/sync/test/integration/migration_watcher.h"
+
+MigrationWaiter::MigrationWaiter(syncer::ModelTypeSet expected_types,
+                                 MigrationWatcher* watcher)
+    : watcher_(watcher), expected_types_(expected_types) {
+  DCHECK(!expected_types_.Empty());
+  watcher_->set_migration_waiter(this);
+}
+
+MigrationWaiter::~MigrationWaiter() {
+  watcher_->clear_migration_waiter();
+}
+
+// Returns true when sync reports that there is no pending migration, and
+// migration is complete for all data types in |expected_types_|.
+bool MigrationWaiter::IsExitConditionSatisfied() {
+  return watcher_->GetMigratedTypes().HasAll(expected_types_) &&
+         !watcher_->HasPendingBackendMigration();
+}
+
+std::string MigrationWaiter::GetDebugMessage() const {
+  return "Waiting to migrate (" + ModelTypeSetToString(expected_types_) +
+         "); " + "Currently migrated: (" +
+         ModelTypeSetToString(watcher_->GetMigratedTypes()) + ")";
+}
+
+void MigrationWaiter::Wait() {
+  if (IsExitConditionSatisfied()) {
+    DVLOG(1) << "Skipping wait: " << GetDebugMessage();
+    return;
+  }
+
+  StartBlockingWait();
+}
+
+void MigrationWaiter::OnMigrationStateChange() {
+  CheckExitCondition();
+}