Reland "[Mac] Fix form control rendering on 10.14 Mojave."

This is a reland of e7652b9e1dbc2a95964864161283f4b8665154f3

Original change's description:
> [Mac] Fix form control rendering on 10.14 Mojave.
> 
> The renderers need to talk to the CVMS server (OpenCL compiler), which
> then outputs codesigned blobs that can be loaded in to the process. This
> is required for drawing the form controls.
> 
> In addition, another Metal bundle location (in /Library) is permitted.
> 
> Bug: 850021, 847518
> Change-Id: I67106972baf5fc55fccd8f7deff3f47cbea076b5
> Reviewed-on: https://chromium-review.googlesource.com/1103127
> Reviewed-by: Greg Kerr <kerrnel@chromium.org>
> Commit-Queue: Robert Sesek <rsesek@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#567877}

Bug: 850021, 847518
Change-Id: Ieb345079a0923d62b034425baacdfc604153c22b
Reviewed-on: https://chromium-review.googlesource.com/1104517
Reviewed-by: Greg Kerr <kerrnel@chromium.org>
Commit-Queue: Robert Sesek <rsesek@chromium.org>
Cr-Commit-Position: refs/heads/master@{#568038}
1 file changed