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

sync/js/js_event_details.h

Index: sync/js/js_event_details.h
diff --git a/sync/js/js_event_details.h b/sync/js/js_event_details.h
index 512264bf291b9621c818dcf53fed2de9ef101dcd..9ca36db46b3f29586874158994a66723aee0c2ef 100644
--- a/sync/js/js_event_details.h
+++ b/sync/js/js_event_details.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.
 
@@ -10,13 +10,14 @@
 #include <string>
 
 #include "base/values.h"
+#include "sync/base/sync_export.h"
 #include "sync/internal_api/public/util/immutable.h"
 
 namespace syncer {
 
 // A thin wrapper around Immutable<DictionaryValue>.  Used for passing
 // around event details to different threads.
-class JsEventDetails {
+class SYNC_EXPORT JsEventDetails {
  public:
   // Uses an empty dictionary.
   JsEventDetails();