SkSL 'key' variables can now be controlled by 'when' expressions

Bug: skia:8880
Change-Id: I075ef57035b37250196d85bc6767eb877e445aa2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/206698
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
diff --git a/src/gpu/effects/GrMixerEffect.cpp b/src/gpu/effects/GrMixerEffect.cpp
index fb0e50e..98e9a47 100644
--- a/src/gpu/effects/GrMixerEffect.cpp
+++ b/src/gpu/effects/GrMixerEffect.cpp
@@ -22,34 +22,34 @@
         GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
         const GrMixerEffect& _outer = args.fFp.cast<GrMixerEffect>();
         (void)_outer;
-        auto weight = _outer.weight();
+        auto weight = _outer.weight;
         (void)weight;
-        fWeightVar =
+        weightVar =
                 args.fUniformHandler->addUniform(kFragment_GrShaderFlag, kHalf_GrSLType, "weight");
         SkString _input0 = SkStringPrintf("%s", args.fInputColor);
         SkString _child0("_child0");
-        this->emitChild(_outer.fp0_index(), _input0.c_str(), &_child0, args);
+        this->emitChild(_outer.fp0_index, _input0.c_str(), &_child0, args);
         fragBuilder->codeAppendf("half4 in0 = %s;", _child0.c_str());
         SkString _input1 = SkStringPrintf("%s", args.fInputColor);
         SkString _child1("_child1");
-        if (_outer.fp1_index() >= 0) {
-            this->emitChild(_outer.fp1_index(), _input1.c_str(), &_child1, args);
+        if (_outer.fp1_index >= 0) {
+            this->emitChild(_outer.fp1_index, _input1.c_str(), &_child1, args);
         } else {
             fragBuilder->codeAppendf("half4 %s;", _child1.c_str());
         }
         fragBuilder->codeAppendf("\nhalf4 in1 = %s ? %s : %s;\n%s = mix(in0, in1, %s);\n",
-                                 _outer.fp1_index() >= 0 ? "true" : "false", _child1.c_str(),
+                                 _outer.fp1_index >= 0 ? "true" : "false", _child1.c_str(),
                                  args.fInputColor, args.fOutputColor,
-                                 args.fUniformHandler->getUniformCStr(fWeightVar));
+                                 args.fUniformHandler->getUniformCStr(weightVar));
     }
 
 private:
     void onSetData(const GrGLSLProgramDataManager& pdman,
                    const GrFragmentProcessor& _proc) override {
         const GrMixerEffect& _outer = _proc.cast<GrMixerEffect>();
-        { pdman.set1f(fWeightVar, (_outer.weight())); }
+        { pdman.set1f(weightVar, (_outer.weight)); }
     }
-    UniformHandle fWeightVar;
+    UniformHandle weightVar;
 };
 GrGLSLFragmentProcessor* GrMixerEffect::onCreateGLSLInstance() const {
     return new GrGLSLMixerEffect();
@@ -59,17 +59,17 @@
 bool GrMixerEffect::onIsEqual(const GrFragmentProcessor& other) const {
     const GrMixerEffect& that = other.cast<GrMixerEffect>();
     (void)that;
-    if (fWeight != that.fWeight) return false;
+    if (weight != that.weight) return false;
     return true;
 }
 GrMixerEffect::GrMixerEffect(const GrMixerEffect& src)
         : INHERITED(kGrMixerEffect_ClassID, src.optimizationFlags())
-        , fFp0_index(src.fFp0_index)
-        , fFp1_index(src.fFp1_index)
-        , fWeight(src.fWeight) {
-    this->registerChildProcessor(src.childProcessor(fFp0_index).clone());
-    if (fFp1_index >= 0) {
-        this->registerChildProcessor(src.childProcessor(fFp1_index).clone());
+        , fp0_index(src.fp0_index)
+        , fp1_index(src.fp1_index)
+        , weight(src.weight) {
+    this->registerChildProcessor(src.childProcessor(fp0_index).clone());
+    if (fp1_index >= 0) {
+        this->registerChildProcessor(src.childProcessor(fp1_index).clone());
     }
 }
 std::unique_ptr<GrFragmentProcessor> GrMixerEffect::clone() const {