Add isSingleComponent bool to getConstantColorComponent

src/effects/gradients/SkGradientShader.cpp

Index: src/effects/gradients/SkGradientShader.cpp
diff --git a/src/effects/gradients/SkGradientShader.cpp b/src/effects/gradients/SkGradientShader.cpp
index d25873b438502c84bd3a880f84524ed6bff21df0..7999b9c75447cc1761f67007ec31cb741a35ee79 100644
--- a/src/effects/gradients/SkGradientShader.cpp
+++ b/src/effects/gradients/SkGradientShader.cpp
@@ -1217,12 +1217,13 @@ bool GrGradientEffect::onIsEqual(const GrProcessor& processor) const {
     return false;
 }
 
-void GrGradientEffect::getConstantColorComponents(GrColor* color, uint32_t* validFlags) const {
-    if (fIsOpaque && (kA_GrColorComponentFlag & *validFlags) && 0xff == GrColorUnpackA(*color)) {
-        *validFlags = kA_GrColorComponentFlag;
+void GrGradientEffect::onComputeInvarientOutput(InvarientOutput* invarientOutput) const {
+    if (fIsOpaque && invarientOutput->hasOpaqueAlpha()) {
+        invarientOutput->validFlags = kA_GrColorComponentFlag;
     } else {
-        *validFlags = 0;
+        invarientOutput->validFlags = 0;
     }
+    invarientOutput->isSingleComponent = false;
 }
 
 int GrGradientEffect::RandomGradientParams(SkRandom* random,