[Sync] Convert sync to a static library.

components/sync/js/sync_js_controller.h

Index: components/sync/js/sync_js_controller.h
diff --git a/components/sync/js/sync_js_controller.h b/components/sync/js/sync_js_controller.h
index 13b757e70fe9d813a4a32873f434213ea8630dcc..79a8400e83cc0f7a8eac48eb4c5c0e709b5e3e21 100644
--- a/components/sync/js/sync_js_controller.h
+++ b/components/sync/js/sync_js_controller.h
@@ -12,7 +12,6 @@
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
-#include "components/sync/base/sync_export.h"
 #include "components/sync/base/weak_handle.h"
 #include "components/sync/js/js_controller.h"
 #include "components/sync/js/js_event_handler.h"
@@ -23,10 +22,9 @@ class JsBackend;
 
 // A class that mediates between the sync JsEventHandlers and the sync
 // JsBackend.
-class SYNC_EXPORT SyncJsController
-    : public JsController,
-      public JsEventHandler,
-      public base::SupportsWeakPtr<SyncJsController> {
+class SyncJsController : public JsController,
+                         public JsEventHandler,
+                         public base::SupportsWeakPtr<SyncJsController> {
  public:
   SyncJsController();