Add isSingleComponent bool to getConstantColorComponent

src/effects/SkColorMatrixFilter.cpp

Index: src/effects/SkColorMatrixFilter.cpp
diff --git a/src/effects/SkColorMatrixFilter.cpp b/src/effects/SkColorMatrixFilter.cpp
index 5ac455253e17db25f7b0efb4c846131212439326..8549fd72e12a719a3f94713218defa1b77dfb930 100644
--- a/src/effects/SkColorMatrixFilter.cpp
+++ b/src/effects/SkColorMatrixFilter.cpp
@@ -349,51 +349,6 @@ public:
         return GrTBackendFragmentProcessorFactory<ColorMatrixEffect>::getInstance();
     }
 
-    virtual void getConstantColorComponents(GrColor* color,
-                                            uint32_t* validFlags) const SK_OVERRIDE {
-        // We only bother to check whether the alpha channel will be constant. If SkColorMatrix had
-        // type flags it might be worth checking the other components.
-
-        // The matrix is defined such the 4th row determines the output alpha. The first four
-        // columns of that row multiply the input r, g, b, and a, respectively, and the last column
-        // is the "translation".
-        static const uint32_t kRGBAFlags[] = {
-            kR_GrColorComponentFlag,
-            kG_GrColorComponentFlag,
-            kB_GrColorComponentFlag,
-            kA_GrColorComponentFlag
-        };
-        static const int kShifts[] = {
-            GrColor_SHIFT_R, GrColor_SHIFT_G, GrColor_SHIFT_B, GrColor_SHIFT_A,
-        };
-        enum {
-            kAlphaRowStartIdx = 15,
-            kAlphaRowTranslateIdx = 19,
-        };
-
-        SkScalar outputA = 0;
-        for (int i = 0; i < 4; ++i) {
-            // If any relevant component of the color to be passed through the matrix is non-const
-            // then we can't know the final result.
-            if (0 != fMatrix.fMat[kAlphaRowStartIdx + i]) {
-                if (!(*validFlags & kRGBAFlags[i])) {
-                    *validFlags = 0;
-                    return;
-                } else {
-                    uint32_t component = (*color >> kShifts[i]) & 0xFF;
-                    outputA += fMatrix.fMat[kAlphaRowStartIdx + i] * component;
-                }
-            }
-        }
-        outputA += fMatrix.fMat[kAlphaRowTranslateIdx];
-        *validFlags = kA_GrColorComponentFlag;
-        // We pin the color to [0,1]. This would happen to the *final* color output from the frag
-        // shader but currently the effect does not pin its own output. So in the case of over/
-        // underflow this may deviate from the actual result. Maybe the effect should pin its
-        // result if the matrix could over/underflow for any component?
-        *color = static_cast<uint8_t>(SkScalarPin(outputA, 0, 255)) << GrColor_SHIFT_A;
-    }
-
     GR_DECLARE_FRAGMENT_PROCESSOR_TEST;
 
     class GLProcessor : public GrGLFragmentProcessor {
@@ -471,6 +426,51 @@ private:
         return cme.fMatrix == fMatrix;
     }
 
+    virtual void onComputeInvariantOutput(InvariantOutput* inout) const SK_OVERRIDE {
+        // We only bother to check whether the alpha channel will be constant. If SkColorMatrix had
+        // type flags it might be worth checking the other components.
+
+        // The matrix is defined such the 4th row determines the output alpha. The first four
+        // columns of that row multiply the input r, g, b, and a, respectively, and the last column
+        // is the "translation".
+        static const uint32_t kRGBAFlags[] = {
+            kR_GrColorComponentFlag,
+            kG_GrColorComponentFlag,
+            kB_GrColorComponentFlag,
+            kA_GrColorComponentFlag
+        };
+        static const int kShifts[] = {
+            GrColor_SHIFT_R, GrColor_SHIFT_G, GrColor_SHIFT_B, GrColor_SHIFT_A,
+        };
+        enum {
+            kAlphaRowStartIdx = 15,
+            kAlphaRowTranslateIdx = 19,
+        };
+
+        SkScalar outputA = 0;
+        for (int i = 0; i < 4; ++i) {
+            // If any relevant component of the color to be passed through the matrix is non-const
+            // then we can't know the final result.
+            if (0 != fMatrix.fMat[kAlphaRowStartIdx + i]) {
+                if (!(inout->fValidFlags & kRGBAFlags[i])) {
+                    inout->fValidFlags = 0;
+                    return;
+                } else {
+                    uint32_t component = (inout->fColor >> kShifts[i]) & 0xFF;
+                    outputA += fMatrix.fMat[kAlphaRowStartIdx + i] * component;
+                }
+            }
+        }
+        outputA += fMatrix.fMat[kAlphaRowTranslateIdx];
+        inout->fValidFlags = kA_GrColorComponentFlag;
+        // We pin the color to [0,1]. This would happen to the *final* color output from the frag
+        // shader but currently the effect does not pin its own output. So in the case of over/
+        // underflow this may deviate from the actual result. Maybe the effect should pin its
+        // result if the matrix could over/underflow for any component?
+        inout->fColor = static_cast<uint8_t>(SkScalarPin(outputA, 0, 255)) << GrColor_SHIFT_A;
+        inout->fIsSingleComponent = false;
+    }
+
     SkColorMatrix fMatrix;
 
     typedef GrFragmentProcessor INHERITED;