1.0.0-alpha.5: $trace.enable() throws error

[christopherthielen]

This is a regression since alpha.4

When trace is enabled app.run($trace => $trace.enable())
the following error is printed to the log:

angular-ui-router.js:2264 Swallowed exception during synchronous hook handler: TypeError: Cannot read property 'name' of undefined

This is caused by uiViewString trying to get the creationContext... should creationContext ever be undefined?