Add isSingleComponent bool to getConstantColorComponent

src/effects/SkLumaColorFilter.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkLumaColorFilter.h"
 
 #include "SkColorPriv.h"
@@ skipping 55 matching lines @@
         GR_CREATE_STATIC_FRAGMENT_PROCESSOR(gLumaEffect, LumaColorFilterEffect, ());
         return SkRef(gLumaEffect);
     }
 
     static const char* Name() { return "Luminance-to-Alpha"; }
 
     virtual const GrBackendFragmentProcessorFactory& getFactory() const SK_OVERRIDE {
         return GrTBackendFragmentProcessorFactory<LumaColorFilterEffect>::getInstance();
     }
 
-    virtual void getConstantColorComponents(GrColor* color,
-                                            uint32_t* validFlags) const SK_OVERRIDE {
-        // The output is always black.
-        *color = GrColorPackRGBA(0, 0, 0, GrColorUnpackA(*color));
-        *validFlags = kRGB_GrColorComponentFlags;
-    }
-
     class GLProcessor : public GrGLFragmentProcessor {
     public:
         GLProcessor(const GrBackendProcessorFactory& factory,
                     const GrProcessor&)
         : INHERITED(factory) {
         }
 
         static void GenKey(const GrProcessor&, const GrGLCaps&, GrProcessorKeyBuilder* b) {}
 
         virtual void emitCode(GrGLProgramBuilder* builder,
@@ skipping 19 matching lines @@
         }
 
     private:
         typedef GrGLFragmentProcessor INHERITED;
     };
 
 private:
     virtual bool onIsEqual(const GrProcessor&) const SK_OVERRIDE {
         return true;
     }
+
+    virtual void onComputeInvariantOutput(InvariantOutput* inout) const SK_OVERRIDE {
+        // The output is always black.
+        inout->fColor = GrColorPackRGBA(0, 0, 0, GrColorUnpackA(inout->fColor));
+        inout->fValidFlags = kRGB_GrColorComponentFlags;
+        inout->fIsSingleComponent = false;
+    }
 };
 
 GrFragmentProcessor* SkLumaColorFilter::asFragmentProcessor(GrContext*) const {
     return LumaColorFilterEffect::Create();
 }
 #endif