When a paint worklet thread takes too long, we would like to move on,
since we have a ~16ms budget for rendering at 60fps. At the moment, there
is no provision in the paintworklet spec to signal such timeouts to the
developer. ajeffrey opened an [issue][1] for this, but it got punted to
v2 of the spec. Hence we are silently timing out unresponsive paint
scripts.
The timeout value is chosen to be 10ms by default, and can be overridden
by setting the SERVO_PAINT_WORKLET_TIMEOUT_MS environment variable.
In the absence of such a timeout, the reftest in this commit would fail
by timing out the testrunner itself, since the paint script never
returns. From my discussions with ajeffrey, this should do until we spec
out a way to signal timeouts to the script developer.
This fixes#17370.
[1]: https://github.com/w3c/css-houdini-drafts/issues/507
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Source-Repo: https://github.com/servo/servo
Source-Revision: 54f8cc37c5a7874607128e3518fd0982f7065565
--HG--
extra : subtree_source : https%3A//hg.mozilla.org/projects/converted-servo-linear
extra : subtree_revision : 0234a7fd5437d1c2a9c0424b9e2bb51d309a4490
cda0c94d8c