Fix local clip rect being applied in transform shader.

[glennw]

This change is 

[glennw]

r? @kvark

Fixes #1732.

This still needs a gecko try run. Passes the servo/wrench tests ok.

[glennw]

There is a gecko try run here, that has some failures.

https://hg.mozilla.org/try/rev/2b2948c12b1d516c5d7bb49a07cd6b1d9ffd1d00
https://treeherder.mozilla.org/#/jobs?repo=try&revision=2b2948c12b1d516c5d7bb49a07cd6b1d9ffd1d00

I think all the failures are intermittent, except for one permanent failure in R4 on layout/reftests/bugs/579323-1.html. I briefly looked at that test and there's no transform elements on it. Given that, I wouldn't expect this test to be affected (since it should be running through the non-transform shader path).

I'll debug it tomorrow, unless @staktrace or @jrmuizel have any ideas about that failure?

[glennw]

Hmmm, that same test is failing (in the same way) for me locally, without this patch applied (just running with current tip). So I think that means this is fine to merge - @staktrace ?

[glennw]

I also verified that none of the items in that test are running through the transform shader path.

[staktrace]

@glennw Yeah this appears to be a pre-existing failure that cropped up sometime last night. I'm chasing down what caused it but it is unrelated to your patches so feel free to land your stuff. Bug 1403457 is tracking the failure if you're interested.

[kvark]

@bors-servo r+

[bors-servo]

📌 Commit 84a2959 has been approved by kvark

[bors-servo]

⌛ Testing commit 84a2959 with merge 6007c07...

[bors-servo]

☀️ Test successful - status-appveyor, status-travis
Approved by: kvark
Pushing 6007c07 to master...