Potentially optimize some GrGLEffects for known input color values

src/gpu/GrAAConvexPathRenderer.cpp

Index: src/gpu/GrAAConvexPathRenderer.cpp
diff --git a/src/gpu/GrAAConvexPathRenderer.cpp b/src/gpu/GrAAConvexPathRenderer.cpp
index 13c26fbb9b2aeecbcc9f6cc39e02719b0f0bbd17..1d2c4cf6582cbee5bd0fa38fce98fb8129c8bf86 100644
--- a/src/gpu/GrAAConvexPathRenderer.cpp
+++ b/src/gpu/GrAAConvexPathRenderer.cpp
@@ -531,7 +531,7 @@ public:
                               const GrDrawEffect& drawEffect,
                               EffectKey key,
                               const char* outputColor,
-                              const char* inputColor,
+                              const GrGLSLExpr4& inputColor,
                               const TransformedCoordsArray&,
                               const TextureSamplerArray& samplers) SK_OVERRIDE {
             const char *vsName, *fsName;
@@ -561,7 +561,7 @@ public:
 
 
             builder->fsCodeAppendf("\t%s = %s;\n", outputColor,
-                                   (GrGLSLExpr4(inputColor) * GrGLSLExpr1("edgeAlpha")).c_str());
+                                   (inputColor * GrGLSLExpr1("edgeAlpha")).c_str());
 
             builder->vsCodeAppendf("\t%s = %s;\n", vsName, attrName->c_str());
         }