[Sync] Convert sync to a static library.

components/sync/sessions_impl/model_type_registry.h

Index: components/sync/sessions_impl/model_type_registry.h
diff --git a/components/sync/sessions_impl/model_type_registry.h b/components/sync/sessions_impl/model_type_registry.h
index 01f2f260abc9257bc8ab4a68685ca9f6d77537aa..fb8d1b27df1ae163f9d71a7d337270621a01d051 100644
--- a/components/sync/sessions_impl/model_type_registry.h
+++ b/components/sync/sessions_impl/model_type_registry.h
@@ -14,7 +14,6 @@
 #include "base/memory/scoped_vector.h"
 #include "base/memory/weak_ptr.h"
 #include "components/sync/base/model_type.h"
-#include "components/sync/base/sync_export.h"
 #include "components/sync/core/model_type_connector.h"
 #include "components/sync/core/non_blocking_sync_common.h"
 #include "components/sync/core/sync_encryption_handler.h"
@@ -46,8 +45,8 @@ typedef std::map<ModelType, DirectoryTypeDebugInfoEmitter*>
     DirectoryTypeDebugInfoEmitterMap;
 
 // Keeps track of the sets of active update handlers and commit contributors.
-class SYNC_EXPORT ModelTypeRegistry : public syncer_v2::ModelTypeConnector,
-                                      public SyncEncryptionHandler::Observer {
+class ModelTypeRegistry : public syncer_v2::ModelTypeConnector,
+                          public SyncEncryptionHandler::Observer {
  public:
   // Constructs a ModelTypeRegistry that supports directory types.
   ModelTypeRegistry(const std::vector<scoped_refptr<ModelSafeWorker>>& workers,