OK, got the overlay to inject, it shows FPS in the corner and the little popup to "press shift+tab" to open appears.
But shift + tab doesn't work automatically. Do I have to detect it and do something?
I tried binding a keypress to open "friends" and got the screen to appear. But I can't close the overlay.
There's an "on overlay deactivated"...
UPDATE I got overlay working properly for windows!
I used sdk 136 / node 0.15
put steam dll in the package.nw file
put api text file in the directory with nw.exe
Needed to add the " --in-process-gpu" option to \Construct2\Construct2-Win64\exporters\html5\nwjs\package-win.json chromium-args line.
Now shift+tab works to bring up overlay and mouse works inside the overlay.
UPDATE 2 F12!
So F12 brings up the chrome debugging tools! Didn't know that! So if someone tries to take a screenshot they also get the debug tools.
Solution is to have an event (on key pressed) that captures F12 but don't do anything inside it. Make sure that event is in every layout.