[sync] Componentize sync: Part 6: Add more SYNC_EXPORTs to files in src/sync/

sync/notifier/state_writer.h

Index: sync/notifier/state_writer.h
diff --git a/sync/notifier/state_writer.h b/sync/notifier/state_writer.h
index 84abd171fe7dee43074e88f76f4923842d57cae5..b40bd45a2453aea1bf38600dc0673a0b43406d93 100644
--- a/sync/notifier/state_writer.h
+++ b/sync/notifier/state_writer.h
@@ -1,4 +1,4 @@
-// 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.
 //
@@ -9,9 +9,11 @@
 
 #include <string>
 
+#include "sync/base/sync_export.h"
+
 namespace syncer {
 
-class StateWriter {
+class SYNC_EXPORT_PRIVATE StateWriter {
  public:
   virtual ~StateWriter() {}