Bug 1720841 - Clamp loop condition variable to static value in cs_blur. r=gw
Bug 1720841 - Clamp loop condition variable to static value in cs_blur. r=gw

In the cs_blur fragment shader there is a for loop with a number of
iterations determined by a flat varying. On some old Adreno drivers
this causes severe issues including hangs and crashes. These can be
avoided by clamping the number of iterations to a statically known
value.

Differential Revision: https://phabricator.services.mozilla.com/D120281

[ghsync] From https://hg.mozilla.org/mozilla-central/rev/16308825081d0f46d658c5b51224009b93dc8041

servo/webrender,servo/webrender,servo/webrender,servo/webrender,servo/webrender,servo/webrender