[Sync] Add support for proxy types

chrome/browser/sync/glue/virtual_data_type_controller.h

Index: chrome/browser/sync/glue/virtual_data_type_controller.h
diff --git a/chrome/browser/sync/glue/virtual_data_type_controller.h b/chrome/browser/sync/glue/virtual_data_type_controller.h
new file mode 100644
index 0000000000000000000000000000000000000000..1c7ffb46400631d1b5c4be3312239ad43dbe2154
--- /dev/null
+++ b/chrome/browser/sync/glue/virtual_data_type_controller.h
@@ -0,0 +1,54 @@
+// Copyright (c) 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.
+
+#ifndef CHROME_BROWSER_SYNC_GLUE_VIRTUAL_DATA_TYPE_CONTROLLER_H__
+#define CHROME_BROWSER_SYNC_GLUE_VIRTUAL_DATA_TYPE_CONTROLLER_H__
+
+#include "base/basictypes.h"
+#include "base/compiler_specific.h"
+#include "chrome/browser/sync/glue/data_type_controller.h"
+
+namespace browser_sync {
+
+// Implementation for virtual datatypes. These are datatype that have no
+// representation in sync, and therefore no change processor or syncable
+// service.
+class VirtualDataTypeController : public DataTypeController {
+ public:
+  explicit VirtualDataTypeController(syncer::ModelType type);
+
+  // DataTypeController interface.
+  virtual void LoadModels(
+      const ModelLoadCallback& model_load_callback) OVERRIDE;
+  virtual void StartAssociating(const StartCallback& start_callback) OVERRIDE;
+  virtual void Stop() OVERRIDE;
+  virtual syncer::ModelType type() const OVERRIDE;
+  virtual syncer::ModelSafeGroup model_safe_group() const OVERRIDE;
+  virtual std::string name() const OVERRIDE;
+  virtual State state() const OVERRIDE;
+
+  // DataTypeErrorHandler interface.
+  virtual void OnSingleDatatypeUnrecoverableError(
+      const tracked_objects::Location& from_here,
+      const std::string& message) OVERRIDE;
+
+ protected:
+  // DataTypeController is RefCounted.
+  virtual ~VirtualDataTypeController();
+
+  // DataTypeController interface.
+  virtual void OnModelLoaded() OVERRIDE;
+
+ private:
+  State state_;
+
+  // The actual type for this controller.
+  syncer::ModelType type_;
+
+  DISALLOW_COPY_AND_ASSIGN(VirtualDataTypeController);
+};
+
+}  // namespace browser_sync
+
+#endif  // CHROME_BROWSER_SYNC_GLUE_VIRTUAL_DATA_TYPE_CONTROLLER_H__