Reason for revert:
This CL changed 1200 images on gold, when I wouldn't expect any diffs from the description.
Original issue's description:
> Add config options to run different GPU APIs to dm and nanobench
>
> Add extended config specification form that can be used to run different
> gpu backend with different APIs.
>
> The configs can be specified with the form:
> gpu(api=string,dit=bool,nvpr=bool,samples=int)
>
> This replaces and removes the --gpuAPI flag.
>
> All existing configs should still work.
>
> Adds following documentation:
>
> out/Debug/dm --help config
>
> Flags:
> --config: type: string default: 565 8888 gpu nonrendering
> Options: 565 8888 debug gpu gpudebug gpudft gpunull msaa16 msaa4
> nonrendering null nullgpu nvprmsaa16 nvprmsaa4 pdf pdf_poppler skp svg
> xps or use extended form 'backend(option=value,...)'.
>
> Extended form: 'backend(option=value,...)'
>
> Possible backends and options:
>
> gpu(api=string,dit=bool,nvpr=bool,samples=int) GPU backend
> api type: string default: native.
> Select graphics API to use with gpu backend.
> Options:
> native Use platform default OpenGL or OpenGL ES backend.
> gl Use OpenGL.
> gles Use OpenGL ES.
> debug Use debug OpenGL.
> null Use null OpenGL.
> dit type: bool default: false.
> Use device independent text.
> nvpr type: bool default: false.
> Use NV_path_rendering OpenGL and OpenGL ES extension.
> samples type: int default: 0.
> Use multisampling with N samples.
>
> Predefined configs:
>
> gpu = gpu()
> msaa4 = gpu(samples=4)
> msaa16 = gpu(samples=16)
> nvprmsaa4 = gpu(nvpr=true,samples=4)
> nvprmsaa16 = gpu(nvpr=true,samples=16)
> gpudft = gpu(dit=true)
> gpudebug = gpu(api=debug)
> gpunull = gpu(api=null)
> debug = gpu(api=debug)
> nullgpu = gpu(api=null)
>
> BUG=skia:2992
>
> Committed: https://skia.googlesource.com/skia/+/e13ca329fca4c28cf4e078561f591ab27b743d23
> GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1490113005
>
> Committed: https://skia.googlesource.com/skia/+/c8b4336444e7b90382e04e33665fb3b8490b825bTBR=mtklein@google.com,bsalomon@google.com,scroggo@google.com,kkinnunen@nvidia.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:2992
Review URL: https://codereview.chromium.org/1536963002
4dabf83cbe