Ok, that is the version I DL'd off google play. Really nice graphics BTW. Runs good on my 'torture-test' low end android, an LG Ultimate 2.
Do you have the crosswalk 10 version anywhere? There's really no good reason I can think of that a game this simple should be giving you any trouble with performance, except on really, really low end devices, or if something is wrong with your code.
Do you have any logic that does dynamic reformating of the canvas size or resolution?
Have you tried debugging with a cpu meter readout? If you do, use a spritefont, and only update it every 0.5 sec (IIRC that's as often as it changes).
From what I've read, crosswalk 10 is definitely a step down in performance from v7, but your game should still be playable, and those results you are getting with WebGL are way out of whack (it should never, ever, be slower).
FYI, the performance drop from cwalk v7 to v10 goes all the way back to chromium/blink base, so don't get too mad at Intel on this one.