Convert the dither runtime effect into a regular .fp effect.

This was previously implemented as a runtime effect in order to dogfood
runtime effects when they were new. However, runtime effects do not
support passing a color to a FP via `sample(fp, inputColor)`, which
is needed to properly implement SkPaintToGrPaint.

Change-Id: Ic826860ab06038f13633be677d79a9138d41db85
Bug: skia:10217
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/301547
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
diff --git a/src/gpu/effects/generated/GrDitherEffect.cpp b/src/gpu/effects/generated/GrDitherEffect.cpp
new file mode 100644
index 0000000..6bdb808
--- /dev/null
+++ b/src/gpu/effects/generated/GrDitherEffect.cpp
@@ -0,0 +1,85 @@
+/*
+ * Copyright 2020 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+/**************************************************************************************************
+ *** This file was autogenerated from GrDitherEffect.fp; do not modify.
+ **************************************************************************************************/
+#include "GrDitherEffect.h"
+
+#include "src/gpu/GrTexture.h"
+#include "src/gpu/glsl/GrGLSLFragmentProcessor.h"
+#include "src/gpu/glsl/GrGLSLFragmentShaderBuilder.h"
+#include "src/gpu/glsl/GrGLSLProgramBuilder.h"
+#include "src/sksl/SkSLCPP.h"
+#include "src/sksl/SkSLUtil.h"
+class GrGLSLDitherEffect : public GrGLSLFragmentProcessor {
+public:
+    GrGLSLDitherEffect() {}
+    void emitCode(EmitArgs& args) override {
+        GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
+        const GrDitherEffect& _outer = args.fFp.cast<GrDitherEffect>();
+        (void)_outer;
+        auto range = _outer.range;
+        (void)range;
+        rangeVar = args.fUniformHandler->addUniform(&_outer, kFragment_GrShaderFlag, kHalf_GrSLType,
+                                                    "range");
+        SkString _input302(args.fInputColor);
+        SkString _sample302;
+        _sample302 = this->invokeChild(_outer.inputFP_index, _input302.c_str(), args);
+        fragBuilder->codeAppendf(
+                R"SkSL(half4 color = %s;
+half value;
+@if (sk_Caps.integerSupport) {
+    uint x = uint(sk_FragCoord.x);
+    uint y = uint(sk_FragCoord.y) ^ x;
+    uint m = (((((y & 1) << 5 | (x & 1) << 4) | (y & 2) << 2) | (x & 2) << 1) | (y & 4) >> 1) | (x & 4) >> 2;
+    value = half(m) / 64.0 - 0.4921875;
+} else {
+    half4 bits = mod(half4(sk_FragCoord.yxyx), half4(2.0, 2.0, 4.0, 4.0));
+    bits.zw = step(2.0, bits.zw);
+    bits.xz = abs(bits.xz - bits.yw);
+    value = dot(bits, half4(0.5, 0.25, 0.125, 0.0625)) - 0.46875;
+}
+%s = half4(clamp(color.xyz + value * %s, 0.0, color.w), color.w);
+)SkSL",
+                _sample302.c_str(), args.fOutputColor,
+                args.fUniformHandler->getUniformCStr(rangeVar));
+    }
+
+private:
+    void onSetData(const GrGLSLProgramDataManager& pdman,
+                   const GrFragmentProcessor& _proc) override {
+        const GrDitherEffect& _outer = _proc.cast<GrDitherEffect>();
+        { pdman.set1f(rangeVar, (_outer.range)); }
+    }
+    UniformHandle rangeVar;
+};
+GrGLSLFragmentProcessor* GrDitherEffect::onCreateGLSLInstance() const {
+    return new GrGLSLDitherEffect();
+}
+void GrDitherEffect::onGetGLSLProcessorKey(const GrShaderCaps& caps,
+                                           GrProcessorKeyBuilder* b) const {}
+bool GrDitherEffect::onIsEqual(const GrFragmentProcessor& other) const {
+    const GrDitherEffect& that = other.cast<GrDitherEffect>();
+    (void)that;
+    if (range != that.range) return false;
+    return true;
+}
+GrDitherEffect::GrDitherEffect(const GrDitherEffect& src)
+        : INHERITED(kGrDitherEffect_ClassID, src.optimizationFlags()), range(src.range) {
+    { inputFP_index = this->cloneAndRegisterChildProcessor(src.childProcessor(src.inputFP_index)); }
+}
+std::unique_ptr<GrFragmentProcessor> GrDitherEffect::clone() const {
+    return std::unique_ptr<GrFragmentProcessor>(new GrDitherEffect(*this));
+}
+GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrDitherEffect);
+#if GR_TEST_UTILS
+std::unique_ptr<GrFragmentProcessor> GrDitherEffect::TestCreate(GrProcessorTestData* d) {
+    float range = d->fRandom->nextRangeF(0.0, 1.0);
+    return GrDitherEffect::Make(GrProcessorUnitTest::MakeChildFP(d), range);
+}
+#endif