Remove unused z-index parameter

[jrmuizel]

This isn't used anywhere inside WebRender and who knows what the
semantics would be. Servo and Gecko both z-sort before creating
WebRender display lists.

---

This change is 

[kvark]

I've also not found any use of it in WR so far.
Leaving for @glennw to have a look.

[glennw]

@bors-servo r+

[bors-servo]

📌 Commit 97b605a has been approved by glennw

[bors-servo]

⌛ Testing commit 97b605a with merge 4c0f3bf...

[bors-servo]

💔 Test failed - status-travis

[glennw]

@bors-servo retry

[bors-servo]

⌛ Testing commit 97b605a with merge 70ca467...

[bors-servo]

💔 Test failed - status-travis

[glennw]

We seem to be hitting some kind of timeout on the mac builder permanently with all the pending PRs. Any suggestions @metajack @larsbergstrom ? Perhaps we could try updating the rustc version?

[jrmuizel]

It looks like this pull request succeeded: #1158

[larsbergstrom]

Yeah, it looks like there's something going on:

No output has been received in the last 10m0s, this potentially indicates a stalled build or something wrong with the build itself.

Check the details on how to adjust your build configuration on: https://docs.travis-ci.com/user/common-build-problems/#Build-times-out-because-no-output-was-received

A 10 minute pause without any output from rustc or it completing seems not unusal, though, considering that even though the build is fast on debug:

Finished dev [unoptimized + debuginfo] target(s) in 49.80 secs

Looking at a successful build on release, it did take 21.95 minutes:

Finished release [optimized + debuginfo] target(s) in 1317.76 secs

I suspect that you should either send mail to support@travis-ci.org to ask them to increase the timeout slightly or use one of the wrappers:
https://docs.travis-ci.com/user/common-build-problems/#Build-times-out-because-no-output-was-received

That said, ~22 minutes seems like a REALLY long time to compile just webrender. Is there something going on here, maybe? Or a compiler regression?

[bors-servo]

☔ The latest upstream changes (presumably #1160) made this pull request unmergeable. Please resolve the merge conflicts.

[glennw]

Other PRs have been getting through today, so maybe it was a travis issue? Let's just retry this once it's rebased.

[kvark]

Retrying...
@bors-servo r+

[bors-servo]

📌 Commit c872232 has been approved by kvark

[bors-servo]

⌛ Testing commit c872232 with merge 5a4c337...

[bors-servo]

☀️ Test successful - status-travis
Approved by: kvark
Pushing 5a4c337 to master...