Create helper functions to use in computeInvariantOutput calls

src/gpu/effects/GrMatrixConvolutionEffect.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include "gl/builders/GrGLProgramBuilder.h"
 #include "GrMatrixConvolutionEffect.h"
 #include "gl/GrGLProcessor.h"
 #include "gl/GrGLSL.h"
@@ skipping 40 matching lines @@
     fConvolveAlpha = m.convolveAlpha();
 }
 
 void GrGLMatrixConvolutionEffect::emitCode(GrGLFPBuilder* builder,
                                            const GrFragmentProcessor& fp,
                                            const GrProcessorKey& key,
                                            const char* outputColor,
                                            const char* inputColor,
                                            const TransformedCoordsArray& coords,
                                            const TextureSamplerArray& samplers) {
-    sk_ignore_unused_variable(inputColor);
     const GrTextureDomain& domain = fp.cast<GrMatrixConvolutionEffect>().domain();
 
     fBoundsUni = builder->addUniform(GrGLProgramBuilder::kFragment_Visibility,
                                      kVec4f_GrSLType, "Bounds");
     fImageIncrementUni = builder->addUniform(GrGLProgramBuilder::kFragment_Visibility,
                                              kVec2f_GrSLType, "ImageIncrement");
     fKernelUni = builder->addUniformArray(GrGLProgramBuilder::kFragment_Visibility,
                                           kFloat_GrSLType,
                                           "Kernel",
                                           fKernelSize.width() * fKernelSize.height());
@@ skipping 195 matching lines @@
     return GrMatrixConvolutionEffect::Create(textures[texIdx],
                                              bounds,
                                              kernelSize,
                                              kernel.get(),
                                              gain,
                                              bias,
                                              kernelOffset,
                                              tileMode,
                                              convolveAlpha);
 }