Use complete type with unique_ptr

Reviewed By: fromcelticpark

Differential Revision: D7114324

fbshipit-source-id: c9305c478ebe31ea35b590b861919fd42f56662d

React/CxxBridge/RCTObjcExecutor.mm

@@ -17,6 +17,7 @@
 #import <cxxreact/JSExecutor.h>
 #import <cxxreact/MessageQueueThread.h>
 #import <cxxreact/ModuleRegistry.h>
+#import <cxxreact/RAMBundleRegistry.h>
 #import <folly/json.h>
 
 namespace facebook {