1583545 - Add linear gradient clips in webrender

Status: NEW

(Core :: Graphics: WebRender, enhancement, P3)

Description

[Nicolas Silva [:nical]]

Right now gradient clips are rendered on the CPU and passed to webrender as image masks. This hurts us on some sites such as https://beta.music.apple.com.

In addition to removing the cost of CPU rendering and texture uploads, this would let us do the same type of segment optimization as we do for rounded rectangles, extraxting out potentially large sections of the mask that have no effect (that would have a large effect on the apple music website for example where gradients are big and the vast majority of the mask is fully opaque).