Express (GLSL expression, possibly known value) pairs as a class

src/core/SkXfermode.cpp

Index: src/core/SkXfermode.cpp
diff --git a/src/core/SkXfermode.cpp b/src/core/SkXfermode.cpp
index ac5cee4e3592954ba4b8c34e558652fba054934d..e3d85676ce901b6ce98855ba3c2cbc305eb6217a 100644
--- a/src/core/SkXfermode.cpp
+++ b/src/core/SkXfermode.cpp
@@ -961,7 +961,7 @@ public:
 
             // We don't try to optimize for this case at all
             if (NULL == inputColor) {
-                builder->fsCodeAppendf("\t\tconst vec4 ones = %s;\n", GrGLSLOnesVecf(4));
+                builder->fsCodeAppendf("\t\tconst vec4 ones = %s;\n", GrGLSLExpr<4>(1).c_str());
                 inputColor = "ones";
             }
             builder->fsCodeAppendf("\t\t// SkXfermode::Mode: %s\n", SkXfermode::ModeName(mode));