Added GrGLFragmentProcessor::EmitArgs struct for use with emitCode()

BUG=skia:

Review URL: https://codereview.chromium.org/1251173002
diff --git a/src/effects/SkTableColorFilter.cpp b/src/effects/SkTableColorFilter.cpp
index 11fdb89..8314f30 100644
--- a/src/effects/SkTableColorFilter.cpp
+++ b/src/effects/SkTableColorFilter.cpp
@@ -379,12 +379,7 @@
 public:
     GLColorTableEffect(const GrProcessor&);
 
-    virtual void emitCode(GrGLFPBuilder*,
-                          const GrFragmentProcessor&,
-                          const char* outputColor,
-                          const char* inputColor,
-                          const TransformedCoordsArray&,
-                          const TextureSamplerArray&) override;
+    virtual void emitCode(EmitArgs&) override;
 
     void setData(const GrGLProgramDataManager&, const GrProcessor&) override;
 
@@ -417,28 +412,24 @@
     pdm.set4fv(fRGBAYValuesUni, 1, rgbaYValues);
 }
 
-void GLColorTableEffect::emitCode(GrGLFPBuilder* builder,
-                                  const GrFragmentProcessor&,
-                                  const char* outputColor,
-                                  const char* inputColor,
-                                  const TransformedCoordsArray&,
-                                  const TextureSamplerArray& samplers) {
+void GLColorTableEffect::emitCode(EmitArgs& args) {
     const char* yoffsets;
-    fRGBAYValuesUni = builder->addUniform(GrGLFPBuilder::kFragment_Visibility,
+    fRGBAYValuesUni = args.fBuilder->addUniform(GrGLFPBuilder::kFragment_Visibility,
                                           kVec4f_GrSLType, kDefault_GrSLPrecision,
                                           "yoffsets", &yoffsets);
     static const float kColorScaleFactor = 255.0f / 256.0f;
     static const float kColorOffsetFactor = 1.0f / 512.0f;
-    GrGLFragmentBuilder* fsBuilder = builder->getFragmentShaderBuilder();
-    if (NULL == inputColor) {
+    GrGLFragmentBuilder* fsBuilder = args.fBuilder->getFragmentShaderBuilder();
+    if (NULL == args.fInputColor) {
         // the input color is solid white (all ones).
         static const float kMaxValue = kColorScaleFactor + kColorOffsetFactor;
         fsBuilder->codeAppendf("\t\tvec4 coord = vec4(%f, %f, %f, %f);\n",
                                kMaxValue, kMaxValue, kMaxValue, kMaxValue);
 
     } else {
-        fsBuilder->codeAppendf("\t\tfloat nonZeroAlpha = max(%s.a, .0001);\n", inputColor);
-        fsBuilder->codeAppendf("\t\tvec4 coord = vec4(%s.rgb / nonZeroAlpha, nonZeroAlpha);\n", inputColor);
+        fsBuilder->codeAppendf("\t\tfloat nonZeroAlpha = max(%s.a, .0001);\n", args.fInputColor);
+        fsBuilder->codeAppendf("\t\tvec4 coord = vec4(%s.rgb / nonZeroAlpha, nonZeroAlpha);\n",
+                               args.fInputColor);
         fsBuilder->codeAppendf("\t\tcoord = coord * %f + vec4(%f, %f, %f, %f);\n",
                               kColorScaleFactor,
                               kColorOffsetFactor, kColorOffsetFactor,
@@ -447,27 +438,27 @@
 
     SkString coord;
 
-    fsBuilder->codeAppendf("\t\t%s.a = ", outputColor);
+    fsBuilder->codeAppendf("\t\t%s.a = ", args.fOutputColor);
     coord.printf("vec2(coord.a, %s.a)", yoffsets);
-    fsBuilder->appendTextureLookup(samplers[0], coord.c_str());
+    fsBuilder->appendTextureLookup(args.fSamplers[0], coord.c_str());
     fsBuilder->codeAppend(";\n");
 
-    fsBuilder->codeAppendf("\t\t%s.r = ", outputColor);
+    fsBuilder->codeAppendf("\t\t%s.r = ", args.fOutputColor);
     coord.printf("vec2(coord.r, %s.r)", yoffsets);
-    fsBuilder->appendTextureLookup(samplers[0], coord.c_str());
+    fsBuilder->appendTextureLookup(args.fSamplers[0], coord.c_str());
     fsBuilder->codeAppend(";\n");
 
-    fsBuilder->codeAppendf("\t\t%s.g = ", outputColor);
+    fsBuilder->codeAppendf("\t\t%s.g = ", args.fOutputColor);
     coord.printf("vec2(coord.g, %s.g)", yoffsets);
-    fsBuilder->appendTextureLookup(samplers[0], coord.c_str());
+    fsBuilder->appendTextureLookup(args.fSamplers[0], coord.c_str());
     fsBuilder->codeAppend(";\n");
 
-    fsBuilder->codeAppendf("\t\t%s.b = ", outputColor);
+    fsBuilder->codeAppendf("\t\t%s.b = ", args.fOutputColor);
     coord.printf("vec2(coord.b, %s.b)", yoffsets);
-    fsBuilder->appendTextureLookup(samplers[0], coord.c_str());
+    fsBuilder->appendTextureLookup(args.fSamplers[0], coord.c_str());
     fsBuilder->codeAppend(";\n");
 
-    fsBuilder->codeAppendf("\t\t%s.rgb *= %s.a;\n", outputColor, outputColor);
+    fsBuilder->codeAppendf("\t\t%s.rgb *= %s.a;\n", args.fOutputColor, args.fOutputColor);
 }
 
 ///////////////////////////////////////////////////////////////////////////////