Follow up from https://phabricator.services.mozilla.com/D89851?id=337950#inline-511186

Methods in MarionetteFrameChild that return just an element representation to the parent actor can avoid the sendQuery call to update the web element reference in MarionetteFrameChild.getElementId. The web element reference can instead be updated in the parent actor (for example, when MarionetteFrameChild.findElement returns).

Tracking marionette-fission-mvp bugs for Fission M7 Beta milestone. We would like Marionette tests to work with Fission before we ride the trains to Beta.

While working on bug 1662460 I noticed that this sync call with the parent process is actually not necessary. The underlying reason simply is that when any message gets received by the parent actor, the fromJSON() method is called, which itself actually adds unknown elements to the stack on its own.

So I'm considering to remove it from getElementId() and move this method to element.js for sharing between different modules.

This has already been removed by my patch on bug 1662460.