[Sync] Convert sync to a static library.

components/sync/core_impl/js_sync_encryption_handler_observer.h

Index: components/sync/core_impl/js_sync_encryption_handler_observer.h
diff --git a/components/sync/core_impl/js_sync_encryption_handler_observer.h b/components/sync/core_impl/js_sync_encryption_handler_observer.h
index 6a0b1577a5384c5adc8613a8aed285649bdbdf93..fc1e831f0a97e37f4ca92e403b0f1c8a8bb71f87 100644
--- a/components/sync/core_impl/js_sync_encryption_handler_observer.h
+++ b/components/sync/core_impl/js_sync_encryption_handler_observer.h
@@ -9,7 +9,6 @@
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
-#include "components/sync/base/sync_export.h"
 #include "components/sync/base/weak_handle.h"
 #include "components/sync/core/sync_encryption_handler.h"
 #include "components/sync/protocol/sync_protocol_error.h"
@@ -24,8 +23,7 @@ class JsEventDetails;
 class JsEventHandler;
 
 // Routes SyncEncryptionHandler events to a JsEventHandler.
-class SYNC_EXPORT JsSyncEncryptionHandlerObserver
-    : public SyncEncryptionHandler::Observer {
+class JsSyncEncryptionHandlerObserver : public SyncEncryptionHandler::Observer {
  public:
   JsSyncEncryptionHandlerObserver();
   ~JsSyncEncryptionHandlerObserver() override;