Revert of Test that GrFragmentProcessors work without input colors.

src/gpu/effects/GrExtractAlphaFragmentProcessor.cpp

Index: src/gpu/effects/GrExtractAlphaFragmentProcessor.cpp
diff --git a/src/gpu/effects/GrExtractAlphaFragmentProcessor.cpp b/src/gpu/effects/GrExtractAlphaFragmentProcessor.cpp
index 8f6af65ca77be81034ab62d8c8f906f5b107a435..c5ee9b8571c285c9b44572fe252c343dbf8fcd8b 100644
--- a/src/gpu/effects/GrExtractAlphaFragmentProcessor.cpp
+++ b/src/gpu/effects/GrExtractAlphaFragmentProcessor.cpp
@@ -14,13 +14,9 @@
     GLExtractAlphaFragmentProcessor() {}
 
     void emitCode(EmitArgs& args) override {
-        if (args.fInputColor) {
-            GrGLFragmentBuilder* fsBuilder = args.fBuilder->getFragmentShaderBuilder();
-            fsBuilder->codeAppendf("vec4 alpha4 = %s.aaaa;", args.fInputColor);
-            this->emitChild(0, "alpha4", args.fOutputColor, args);
-        } else {
-            this->emitChild(0, nullptr, args.fOutputColor, args);
-        }
+        GrGLFragmentBuilder* fsBuilder = args.fBuilder->getFragmentShaderBuilder();
+        fsBuilder->codeAppendf("vec4 alpha4 = %s.aaaa;", args.fInputColor);
+        this->emitChild(0, "alpha4", args.fOutputColor, args);
     }
 
 private: