Revert of Abstracted diffuse color map out of SkLightingShaderImpl into a generic...

Revert of Abstracted diffuse color map out of SkLightingShaderImpl into a generic SkShader (patchset #11 id:200001 of https://codereview.chromium.org/2062703003/ )

Reason for revert:
Causing the Test-Ubuntu-GCC-ShuttleA-GPU-GTX550Ti-x86_64-Release-Valgrind builder to fail.

Started failing at this build:
https://uberchromegw.corp.google.com/i/client.skia/builders/Test-Ubuntu-GCC-ShuttleA-GPU-GTX550Ti-x86_64-Release-Valgrind/builds/1214

Snippet from build log:

==3016== Invalid read of size 4
==3016==    at 0xCD1901: GrFragmentProcessor::registerChildProcessor(sk_sp<GrFragmentProcessor>) (SkTArray.h:163)
==3016==    by 0xA58B47: _Z10sk_make_spI11NormalMapFPI5sk_spI19GrFragmentProcessorERK8SkMatrixEES1_IT_EDpOT0_ (SkNormalSource.cpp:84)
==3016==    by 0xA582E8: NormalMapSourceImpl::asFragmentProcessor(GrContext*, SkMatrix const&, SkMatrix const*, SkFilterQuality, SkSourceGammaTreatment) const (SkNormalSource.cpp:187)
==3016==    by 0xA0ADB5: SkLightingShaderImpl::asFragmentProcessor(GrContext*, SkMatrix const&, SkMatrix const*, SkFilterQuality, SkSourceGammaTreatment) const (SkLightingShader.cpp:268)
==3016==    by 0xDA17E6: skpaint_to_grpaint_impl(GrContext*, SkPaint const&, SkMatrix const&, sk_sp<GrFragmentProcessor>*, SkXfermode::Mode*, bool, bool, GrPaint*) (SkGr.cpp:552)
==3016==    by 0xDA4532: SkPaintToGrPaint(GrContext*, SkPaint const&, SkMatrix const&, bool, GrPaint*) (SkGr.cpp:668)
==3016==    by 0xD99B51: SkGpuDevice::drawRect(SkDraw const&, SkRect const&, SkPaint const&) (SkGpuDevice.cpp:534)
==3016==    by 0x9DDB1C: SkCanvas::onDrawRect(SkRect const&, SkPaint const&) (SkCanvas.cpp:2148)
==3016==    by 0x9DBF40: SkCanvas::drawRect(SkRect const&, SkPaint const&) (SkCanvas.cpp:1919)
==3016==    by 0x8D2A55: skiagm::LightingShaderGM::onDraw(SkCanvas*) (lightingshader.cpp:110)
==3016==    by 0x625659: skiagm::GM::drawContent(SkCanvas*) (gm.cpp:32)
==3016==    by 0x6256AD: skiagm::GM::draw(SkCanvas*) (gm.cpp:24)
==3016==    by 0x61B747: DM::GMSrc::draw(SkCanvas*) const (DMSrcSink.cpp:61)
==3016==    by 0x61F37B: DM::GPUSink::draw(DM::Src const&, SkBitmap*, SkWStream*, SkString*) const (DMSrcSink.cpp:1115)
==3016==    by 0x619261: dm_main() (DM.cpp:1016)
==3016==    by 0x619841: main (DM.cpp:1409)
==3016==  Address 0xf4 is not stack'd, malloc'd or (recently) free'd
==3016==

Caught signal 11 [Segmentation fault], was running:
	gpu gm  lightingshader

Original issue's description:
> Abstracted diffuse color map out of SkLightingShaderImpl into a generic SkShader
>
> Will not run until after landing https://codereview.chromium.org/2106893003/
>
> This CL's base is the CL for the addition of NormalSource to the API: https://codereview.chromium.org/2063793002/
>
> BUG=skia:
> GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2062703003
>
> Committed: https://skia.googlesource.com/skia/+/3f58cd0eb8bf4499c4f179aa6111d7e005809df8

TBR=egdaniel@google.com,robertphillips@google.com,dvonbeck@google.com
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=skia:
NOTRY=true

Review-Url: https://codereview.chromium.org/2137513002