[sync] Componentize sync: Part 2: Add SYNC_EXPORTs to files in src/sync/

sync/internal_api/public/read_transaction.h

-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// 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 SYNC_INTERNAL_API_PUBLIC_READ_TRANSACTION_H_
 #define SYNC_INTERNAL_API_PUBLIC_READ_TRANSACTION_H_
 
 #include "base/compiler_specific.h"
+#include "sync/base/sync_export.h"
 #include "sync/internal_api/public/base_transaction.h"
 
 namespace tracked_objects {
 class Location;
 }  // namespace tracked_objects
 
 namespace syncer {
 
 struct UserShare;
 
 // Sync API's ReadTransaction is a read-only BaseTransaction.  It wraps
 // a syncable::ReadTransaction.
-class ReadTransaction : public BaseTransaction {
+class SYNC_EXPORT ReadTransaction : public BaseTransaction {
  public:
   // Start a new read-only transaction on the specified repository.
   ReadTransaction(const tracked_objects::Location& from_here,
                   UserShare* share);
 
   // Resume the middle of a transaction. Will not close transaction.
   ReadTransaction(UserShare* share, syncable::BaseTransaction* trans);
 
   virtual ~ReadTransaction();
 
@@ skipping 10 matching lines @@
   // The underlying syncable object which this class wraps.
   syncable::BaseTransaction* transaction_;
   bool close_transaction_;
 
   DISALLOW_COPY_AND_ASSIGN(ReadTransaction);
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_INTERNAL_API_PUBLIC_READ_TRANSACTION_H_