On b2g we run with jsloader.reuseGlobal set to true, so we need to modify HawkClient with that in mind. ************************************************************ * Call to xpconnect wrapped JSObject produced this error: * [Exception... "[JavaScript Error: "HawkClient is not a constructor" {file: "resource://gre/modules/FxAccountsClient.jsm" line: 57}]'[JavaScript Error: "HawkClient is not a constructor" {file: "resource://gre/modules/FxAccountsClient.jsm" line: 57}]' when calling method: [nsIDOMEventListener::handleEvent]" nsresult: "0x80570021 (NS_ERROR_XPC_JAVASCRIPT_ERROR_WITH_DETAILS)" location: "JS frame :: app://system.gaiamobile.org/js/fxa_client.js :: sendMessage :: line 35" data: yes] ************************************************************