sync: Change progress marker checking in tests

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 <vector>
+
+#include "base/basictypes.h"
+#include "base/compiler_specific.h"
+#include "base/memory/scoped_vector.h"
+#include "chrome/browser/sync/test/integration/status_change_checker.h"
+
+class ProfileSyncService;
+class ProgressMarkerWatcher;
+class ProfileSyncServiceHarness;
+
+// Waits until all provided clients have finished committing any unsynced items
+// and downloading each others' udpates.
+//
+// This requires that "self-notifications" be enabled.  Otherwise the clients
+// will not fetch the latest progress markers on their own, and the latest
+// progress markers are needed to confirm that clients are in sync.
+//
+// There is a race condition here.  If we manage to perform the check at
+// 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<ProfileSyncService*> services);
+  virtual ~QuiesceStatusChangeChecker();
+
+  virtual bool IsExitConditionSatisfied() OVERRIDE;
+  virtual std::string GetDebugMessage() const OVERRIDE;
+  virtual void InitObserver(ProfileSyncServiceHarness* harness) OVERRIDE;
+  virtual void UninitObserver(ProfileSyncServiceHarness* harness) OVERRIDE;
+
+  void OnServiceStateChanged(ProfileSyncService* service);
+
+ private:
+  std::vector<ProfileSyncService*> services_;
+  ScopedVector<ProgressMarkerWatcher> observers_;
+  ProfileSyncServiceHarness* harness_;
+
+  DISALLOW_COPY_AND_ASSIGN(QuiesceStatusChangeChecker);
+};
+
+#endif  // CHROME_BROWSER_SYNC_TEST_INTEGRATION_QUIESCE_STATUS_CHANGE_CHECKER_H_