Merge 193302 "Force GPU switch with CGLSetVirtualScreen only for..."

Merge 193302 "Force GPU switch with CGLSetVirtualScreen only for..."

> Force GPU switch with CGLSetVirtualScreen only for compositor
> 
> Only compositor contexts are known to use only the subset of GL
> that can be safely migrated between the iGPU and the dGPU. Mark
> those contexts as safe to forcibly transition between the GPUs.
> 
> In particular, Intel GPUs support using a GL_STENCIL_INDEX8
> attachment with no depth buffer, but NV GPUs don't. Skia will use
> this FBO combo if it is listed as available.
> 
> If we use this combo on the iGPU and then forcibly transition the
> GL context using this combo from the iGPU to the dGPU, corruption
> occurs on NV, and a hang happens on AMD.
> 
> Further, if we cache complete FBO combos, then we will cache this
> combo as valid when using the iGPU, and claim that it's valid when
> using the dGPU, resulting in GL errors.
> 
> BUG=180876
> 
> Review URL: https://chromiumcodereview.appspot.com/13746002

TBR=ccameron@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=194413

[kareng, 2013-04-16 19:25:41]

Committed patchset #1 manually as r194413.

[Ken Russell (switch to Gerrit), 2013-04-16 20:24:48]

Anantha and QA team: please see
https://code.google.com/p/chromium/issues/detail?id=180876#c96 for the testing
scenarios for this merge.

[ananthak, 2013-04-17 00:23:09]

Thanks for the detailed instructions. Team will verify them once the build
is available.


On Tue, Apr 16, 2013 at 1:24 PM, <kbr@chromium.org> wrote:

> Anantha and QA team: please see
>
https://code.google.com/p/**chromium/issues/detail?id=**180876#c96<https://co...
the testing
> scenarios for this merge.
>
>
>
https://codereview.chromium.**org/13957008/<https://codereview.chromium.org/1...
>