sync: Finish the SyncScheduler refactor

sync/sessions/nudge_tracker.h

+// Copyright 2013 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.
+//
+// A class to track the outstanding work required to bring the client back into
+// sync with the server.
+#ifndef SYNC_SESSIONS_NUDGE_TRACKER_H_
+#define SYNC_SESSIONS_NUDGE_TRACKER_H_
+
+#include <vector>
+
+#include "base/compiler_specific.h"
+#include "sync/base/sync_export.h"
+#include "sync/internal_api/public/sessions/sync_source_info.h"
+
+namespace syncer {
+namespace sessions {
+
+struct SyncSourceInfo;
+
+class SYNC_EXPORT_PRIVATE NudgeTracker {
+ public:
+  NudgeTracker();
+  ~NudgeTracker();
+
+  // Merges in the information from another nudge.
+  void CoalesceSources(const SyncSourceInfo& source);
+
+  // Returns true if there are no unserviced nudges.
+  bool IsEmpty();
+
+  // Clear all unserviced nudges.
+  void Reset();
+
+  // Returns the coalesced source info.
+  const SyncSourceInfo& source_info() const {
+    return source_info_;
+  }
+
+  // Returns the set of locally modified types, according to our tracked source
+  // infos.  The result is often wrong; see implementation comment for details.
+  ModelTypeSet GetLocallyModifiedTypes() const;
+
+ private:
+  // Merged source info for the nudge(s).
+  SyncSourceInfo source_info_;
+
+  DISALLOW_COPY_AND_ASSIGN(NudgeTracker);
+};
+
+}  // namespace sessions
+}  // namespace syncer
+
+#endif  // SYNC_SESSIONS_NUDGE_TRACKER_H_