Force editor layer for faster paint.

[Tihauan]

Implement the layer separation suggested in [1] to reduce the print area when scrolling. The editor will get its own GPU accelerated layer [2]. It applies to Chrome/WebKit.

Before

After

[1] Tricks for high performance scrolling
[2] Accelerated Rendering in Chrome

[writemonkey]

This will disable editor's subpixel anti aliasing.

[marijnh]

That's definitely a downside. And there are other invasive effects from applying transforms. Since this is easy enough to enable with a custom CSS rule if you really want it, I think I'd prefer not to merge this.

[marijnh]

Closing until further notice.