Create fragment processor for performing input color blend with child processor

src/gpu/gl/GrGLBlend.cpp

Index: src/gpu/gl/GrGLBlend.cpp
diff --git a/src/gpu/gl/GrGLBlend.cpp b/src/gpu/gl/GrGLBlend.cpp
deleted file mode 100644
index 4179ec0b535565c0ae5de57c76f4ef3006c26959..0000000000000000000000000000000000000000
--- a/src/gpu/gl/GrGLBlend.cpp
+++ /dev/null
@@ -1,70 +0,0 @@
-/*
- * Copyright 2015 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-#include "GrGLBlend.h"
-#include "gl/builders/GrGLFragmentShaderBuilder.h"
-
-static bool append_porterduff_term(GrGLFragmentBuilder* fsBuilder, SkXfermode::Coeff coeff,
-                                   const char* colorName, const char* srcColorName,
-                                   const char* dstColorName, bool hasPrevious) {
-    if (SkXfermode::kZero_Coeff == coeff) {
-        return hasPrevious;
-    } else {
-        if (hasPrevious) {
-            fsBuilder->codeAppend(" + ");
-        }
-        fsBuilder->codeAppendf("%s", colorName);
-        switch (coeff) {
-            case SkXfermode::kOne_Coeff:
-                break;
-            case SkXfermode::kSC_Coeff:
-                fsBuilder->codeAppendf(" * %s", srcColorName);
-                break;
-            case SkXfermode::kISC_Coeff:
-                fsBuilder->codeAppendf(" * (vec4(1.0) - %s)", srcColorName);
-                break;
-            case SkXfermode::kDC_Coeff:
-                fsBuilder->codeAppendf(" * %s", dstColorName);
-                break;
-            case SkXfermode::kIDC_Coeff:
-                fsBuilder->codeAppendf(" * (vec4(1.0) - %s)", dstColorName);
-                break;
-            case SkXfermode::kSA_Coeff:
-                fsBuilder->codeAppendf(" * %s.a", srcColorName);
-                break;
-            case SkXfermode::kISA_Coeff:
-                fsBuilder->codeAppendf(" * (1.0 - %s.a)", srcColorName);
-                break;
-            case SkXfermode::kDA_Coeff:
-                fsBuilder->codeAppendf(" * %s.a", dstColorName);
-                break;
-            case SkXfermode::kIDA_Coeff:
-                fsBuilder->codeAppendf(" * (1.0 - %s.a)", dstColorName);
-                break;
-            default:
-                SkFAIL("Unsupported Blend Coeff");
-        }
-        return true;
-    }
-}
-
-void GrGLBlend::AppendPorterDuffBlend(GrGLFragmentBuilder* fsBuilder, const char* srcColor,
-                                      const char* dstColor, const char* outColor,
-                                      SkXfermode::Mode mode) {
-
-    SkXfermode::Coeff srcCoeff, dstCoeff;
-    SkXfermode::ModeAsCoeff(mode, &srcCoeff, &dstCoeff);
-
-    fsBuilder->codeAppendf("%s = ", outColor);
-    // append src blend
-    bool didAppend = append_porterduff_term(fsBuilder, srcCoeff, srcColor, srcColor, dstColor,
-                                            false);
-    // append dst blend
-    if(!append_porterduff_term(fsBuilder, dstCoeff, dstColor, srcColor, dstColor, didAppend)) {
-        fsBuilder->codeAppend("vec4(0, 0, 0, 0)");
-    }
-    fsBuilder->codeAppend(";");
-}