Canvas2D getImageData warning

[pecoram]

Chrome console gives this warning:

Canvas2D: Multiple readback operations using getImageData are faster with the willReadFrequently attribute set to true. See: https://html.spec.whatwg.org/multipage/canvas.html#concept-canvas-will-read-frequently

[wouterlucas]

I think we need to be careful with that, because the way I understand the flag it may flip it to be software instead of hardware accelerated.

As per the note:

CanvasRenderingContext2D objects with will read frequently equal to true tell the user agent that the webpage is likely to perform many readback operations and that it is advantageous to use a software canvas.

Which - dependent on how the engine handles that - might be disadvantageous on lower end devices with very limited CPU power.

I'd not do this until we know, with a high level of confidence, it wont negatively impact performance on SmartTVs / STBs.