Split up SyncEngineEventListener callbacks

sync/engine/sync_cycle_event.h

+// Copyright 2012 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 SYNC_ENGINE_SYNC_CYCLE_EVENT_H_
+#define SYNC_ENGINE_SYNC_CYCLE_EVENT_H_
+
+#include "sync/base/sync_export.h"
+#include "sync/internal_api/public/sessions/sync_session_snapshot.h"
+
+namespace syncer {
+
+struct SyncProtocolError;
+
+struct SYNC_EXPORT_PRIVATE SyncCycleEvent {
+  enum EventCause {
+    ////////////////////////////////////////////////////////////////
+    // Sent on entry of Syncer state machine
+    SYNC_CYCLE_BEGIN,
+
+    // Sent any time progress is made during a sync cycle.
+    STATUS_CHANGED,
+
+    // We have reached the SYNCER_END state in the main sync loop.
+    SYNC_CYCLE_ENDED,
+  };
+
+  explicit SyncCycleEvent(EventCause cause);
+  ~SyncCycleEvent();
+
+  EventCause what_happened;
+
+  // The last session used for syncing.
+  sessions::SyncSessionSnapshot snapshot;
+};
+
+}  // namespace syncer
+
+#endif  // SYNC_ENGINE_SYNC_CYCLE_EVENT_H_