[Sync] Convert sync to a static library.

components/sync/base/nigori.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 COMPONENTS_SYNC_BASE_NIGORI_H_
 #define COMPONENTS_SYNC_BASE_NIGORI_H_
 
 #include <stddef.h>
 
 #include <memory>
 #include <string>
 
-#include "components/sync/base/sync_export.h"
-
 namespace crypto {
 class SymmetricKey;
 }  // namespace crypto
 
 namespace syncer {
 
 // A (partial) implementation of Nigori, a protocol to securely store secrets in
 // the cloud. This implementation does not support server authentication or
 // assisted key derivation.
 //
 // To store secrets securely, use the |Permute| method to derive a lookup name
 // for your secret (basically a map key), and |Encrypt| and |Decrypt| to store
 // and retrieve the secret.
 //
 // https://www.cl.cam.ac.uk/~drt24/nigori/nigori-overview.pdf
-class SYNC_EXPORT Nigori {
+class Nigori {
  public:
   enum Type {
     Password = 1,
   };
 
   Nigori();
   virtual ~Nigori();
 
   // Initialize the client with the given |hostname|, |username| and |password|.
   bool InitByDerivation(const std::string& hostname,
@@ skipping 38 matching lines @@
 
  private:
   std::unique_ptr<crypto::SymmetricKey> user_key_;
   std::unique_ptr<crypto::SymmetricKey> encryption_key_;
   std::unique_ptr<crypto::SymmetricKey> mac_key_;
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_BASE_NIGORI_H_