[Sync] Add sync_export.h (Step 1 for componentizing sync)

sync/internal_api/public/engine/model_safe_worker.h

 // Copyright (c) 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_INTERNAL_API_PUBLIC_ENGINE_MODEL_SAFE_WORKER_H_
 #define SYNC_INTERNAL_API_PUBLIC_ENGINE_MODEL_SAFE_WORKER_H_
 
 #include <map>
 #include <string>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
+#include "sync/base/sync_export.h"
 #include "sync/internal_api/public/base/model_type.h"
 #include "sync/internal_api/public/base/model_type_payload_map.h"
 #include "sync/internal_api/public/util/syncer_error.h"
 
 namespace base {
 class DictionaryValue;
 }  // namespace
 
 namespace syncer {
 
+// TODO(akalin): Move the non-exported functions in this file to a
+// private header.
+
 typedef base::Callback<enum SyncerError(void)> WorkCallback;
 
 enum ModelSafeGroup {
   GROUP_PASSIVE = 0,   // Models that are just "passively" being synced; e.g.
                        // changes to these models don't need to be pushed to a
                        // native model.
   GROUP_UI,            // Models that live on UI thread and are being synced.
   GROUP_DB,            // Models that live on DB thread and are being synced.
   GROUP_FILE,          // Models that live on FILE thread and are being synced.
   GROUP_HISTORY,       // Models that live on history thread and are being
                        // synced.
   GROUP_PASSWORD,      // Models that live on the password thread and are
                        // being synced.  On windows and linux, this runs on the
                        // DB thread.
   MODEL_SAFE_GROUP_COUNT,
 };
 
-std::string ModelSafeGroupToString(ModelSafeGroup group);
+SYNC_EXPORT std::string ModelSafeGroupToString(ModelSafeGroup group);
 
 // The Syncer uses a ModelSafeWorker for all tasks that could potentially
 // modify syncable entries (e.g under a WriteTransaction). The ModelSafeWorker
 // only knows how to do one thing, and that is take some work (in a fully
 // pre-bound callback) and have it performed (as in Run()) from a thread which
 // is guaranteed to be "model-safe", where "safe" refers to not allowing us to
 // cause an embedding application model to fall out of sync with the
 // syncable::Directory due to a race.
-class ModelSafeWorker : public base::RefCountedThreadSafe<ModelSafeWorker> {
+class SYNC_EXPORT ModelSafeWorker
+    : public base::RefCountedThreadSafe<ModelSafeWorker> {
  public:
   // Any time the Syncer performs model modifications (e.g employing a
   // WriteTransaction), it should be done by this method to ensure it is done
   // from a model-safe thread.
   virtual SyncerError DoWorkAndWaitUntilDone(const WorkCallback& work) = 0;
 
   virtual ModelSafeGroup GetModelSafeGroup() = 0;
 
  protected:
   virtual ~ModelSafeWorker();
 
  private:
   friend class base::RefCountedThreadSafe<ModelSafeWorker>;
 };
 
 // A map that details which ModelSafeGroup each syncer::ModelType
 // belongs to.  Routing info can change in response to the user enabling /
 // disabling sync for certain types, as well as model association completions.
 typedef std::map<syncer::ModelType, ModelSafeGroup>
     ModelSafeRoutingInfo;
 
 // Caller takes ownership of return value.
 base::DictionaryValue* ModelSafeRoutingInfoToValue(
     const ModelSafeRoutingInfo& routing_info);
 
-std::string ModelSafeRoutingInfoToString(
+SYNC_EXPORT std::string ModelSafeRoutingInfoToString(
     const ModelSafeRoutingInfo& routing_info);
 
 // Make a ModelTypePayloadMap for all the enabled types in a
 // ModelSafeRoutingInfo using a default payload.
 syncer::ModelTypePayloadMap ModelSafeRoutingInfoToPayloadMap(
     const ModelSafeRoutingInfo& routes,
     const std::string& payload);
 
-syncer::ModelTypeSet GetRoutingInfoTypes(
+SYNC_EXPORT syncer::ModelTypeSet GetRoutingInfoTypes(
     const ModelSafeRoutingInfo& routing_info);
 
-ModelSafeGroup GetGroupForModelType(const syncer::ModelType type,
-                                    const ModelSafeRoutingInfo& routes);
+SYNC_EXPORT ModelSafeGroup GetGroupForModelType(
+    const syncer::ModelType type,
+    const ModelSafeRoutingInfo& routes);
 
 }  // namespace syncer
 
 #endif  // SYNC_INTERNAL_API_PUBLIC_ENGINE_MODEL_SAFE_WORKER_H_