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

sync/internal_api/public/write_transaction.h

Index: sync/internal_api/public/write_transaction.h
diff --git a/sync/internal_api/public/write_transaction.h b/sync/internal_api/public/write_transaction.h
index 8c11570c37b88796331dc1366d620ba809eccd82..9008b4f2b8a35ef72dc5f5f56da0bdad9564a1ba 100644
--- a/sync/internal_api/public/write_transaction.h
+++ b/sync/internal_api/public/write_transaction.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.
 
@@ -7,6 +7,7 @@
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
+#include "sync/base/sync_export.h"
 #include "sync/internal_api/public/base_transaction.h"
 
 namespace tracked_objects {
@@ -25,7 +26,7 @@ class WriteTransaction;
 //
 // NOTE: Only a single model type can be mutated for a given
 // WriteTransaction.
-class WriteTransaction : public BaseTransaction {
+class SYNC_EXPORT WriteTransaction : public BaseTransaction {
  public:
   // Start a new read/write transaction.
   WriteTransaction(const tracked_objects::Location& from_here,