Revert of Implement Porter Duff XP with a blend table (patchset #12 id:220001 of https://codereview.chromium.org/1124373002/)

Reason for revert:
Blocking DEPS roll into Chromium. Crashing virtual/gpu/fast/canvas/canvas-composite-*.html tests with the assert

../../third_party/skia/src/gpu/gl/builders/GrGLFragmentShaderBuilder.cpp:281: failed assertion "k110_GrGLSLGeneration != gpu->glslGeneration() || fOutputs.empty()"

Original issue's description:
> Implement Porter Duff XP with a blend table
>
> Removes the runtime logic used by PorterDuffXferProcessor to decide
> blend coeffs and shader outputs, and instead uses a compile-time
> constant table of pre-selected blend formulas.
>
> Introduces a new blend strategy for srcCoeff=0 that can apply coverage
> with a reverse subtract blend equation instead of dual source
> blending.
>
> Adds new macros in GrBlend.h to analyze blend formulas both runtime.
>
> Removes kSetCoverageDrawing_OptFlag and GrSimplifyBlend as they are no
> longer used.
>
> Adds a GM that verifies all xfermodes, including arithmetic, with the
> color/coverage invariants used by Porter Duff.
>
> Adds a unit test that verifies each Porter Duff formula with every
> color/coverage invariant.
>
> Major changes:
>
>  * Uses a reverse subtract blend equation for coverage when srcCoeff=0
>    (clear, dst-out [Sa=1], dst-in, modulate). Platforms that don't
>    support dual source blending no longer require a dst copy for
>    dst-in and modulate.
>
>  * Sets BlendInfo::fWriteColor to false when the blend does not modify
>    the dst. GrGLGpu will now use glColorMask instead of blending for
>    these modes (dst, dst-in [Sa=1], modulate ignored for [Sc=1]).
>
>  * Converts all SA blend coeffs to One for opaque inputs, and ISA to
>    Zero if there is also no coverage. (We keep ISA around when there
>    is coverage because we use it to tweak alpha for coverage.)
>
>  * Abandons solid white optimizations for the sake of simplicity
>    (screen was the only mode that previous had solid white opts).
>
> Minor differences:
>
>  * Inconsequential differences in opt flags (e.g. we now return
>    kCanTweakAlphaForCoverage_OptFlag even when there is no coverage).
>
>  * Src coeffs when the shader outputs 0.
>
>  * IS2C vs IS2A when the secondary output is scalar.
>
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/9a70920db22b6309c671f8e5d519bb95570e4414

TBR=egdaniel@google.com,bsalomon@google.com,cdalton@nvidia.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review URL: https://codereview.chromium.org/1153993002

1 files changed, 4 insertions, 5 deletions

diff --git a/include/gpu/effects/GrPorterDuffXferProcessor.h b/include/gpu/effects/GrPorterDuffXferProcessor.h
index 56ddb372b4..481b373c10 100644
--- a/include/gpu/effects/GrPorterDuffXferProcessor.h
+++ b/include/gpu/effects/GrPorterDuffXferProcessor.h
@@ -24,7 +24,7 @@ public:
                             GrXPFactory::InvariantOutput*) const override;
 
 private:
-    GrPorterDuffXPFactory(SkXfermode::Mode);
+    GrPorterDuffXPFactory(GrBlendCoeff src, GrBlendCoeff dst); 
 
     GrXferProcessor* onCreateXferProcessor(const GrCaps& caps,
                                            const GrProcOptInfo& colorPOI,
@@ -37,15 +37,14 @@ private:
 
     bool onIsEqual(const GrXPFactory& xpfBase) const override {
         const GrPorterDuffXPFactory& xpf = xpfBase.cast<GrPorterDuffXPFactory>();
-        return fXfermode == xpf.fXfermode;
+        return (fSrcCoeff == xpf.fSrcCoeff && fDstCoeff == xpf.fDstCoeff);
     }
 
     GR_DECLARE_XP_FACTORY_TEST;
-    static void TestGetXPOutputTypes(const GrXferProcessor*, int* outPrimary, int* outSecondary);
 
-    SkXfermode::Mode fXfermode;
+    GrBlendCoeff fSrcCoeff;
+    GrBlendCoeff fDstCoeff;
 
-    friend class GrPorterDuffTest; // for TestGetXPOutputTypes()
     typedef GrXPFactory INHERITED;
 };