Potentially optimize some GrGLEffects for known input color values

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 51eb7c321f6b3d8fa379d09ce5571413ee5922ad..fa6522cbe122b3decb760ec7b3d23a7a9eace1a0 100644
--- a/src/effects/gradients/SkGradientShader.cpp
+++ b/src/effects/gradients/SkGradientShader.cpp
@@ -934,7 +934,7 @@ void GrGLGradientEffect::emitColor(GrGLShaderBuilder* builder,
                                    const char* gradientTValue,
                                    EffectKey key,
                                    const char* outputColor,
-                                   const char* inputColor,
+                                   const GrGLSLExpr4& inputColor,
                                    const TextureSamplerArray& samplers) {
     if (GrGradientEffect::kTwo_ColorType == ColorTypeFromKey(key)){
         builder->fsCodeAppendf("\tvec4 colorTemp = mix(%s, %s, clamp(%s, 0.0, 1.0));\n",
@@ -951,7 +951,7 @@ void GrGLGradientEffect::emitColor(GrGLShaderBuilder* builder,
         }
 
         builder->fsCodeAppendf("\t%s = %s;\n", outputColor,
-                               (GrGLSLExpr4(inputColor) * GrGLSLExpr4("colorTemp")).c_str());
+                               (inputColor * GrGLSLExpr4("colorTemp")).c_str());
     } else if (GrGradientEffect::kThree_ColorType == ColorTypeFromKey(key)){
         builder->fsCodeAppendf("\tfloat oneMinus2t = 1.0 - (2.0 * (%s));\n",
                                gradientTValue);
@@ -975,7 +975,7 @@ void GrGLGradientEffect::emitColor(GrGLShaderBuilder* builder,
         }
 
         builder->fsCodeAppendf("\t%s = %s;\n", outputColor,
-                               (GrGLSLExpr4(inputColor) * GrGLSLExpr4("colorTemp")).c_str());
+                               (inputColor * GrGLSLExpr4("colorTemp")).c_str());
     } else {
         builder->fsCodeAppendf("\tvec2 coord = vec2(%s, %s);\n",
                                gradientTValue,