Expand modulate, add, subtract, extract component glsl helpers.
Review URL: https://codereview.chromium.org/13895006

git-svn-id: http://skia.googlecode.com/svn/trunk@8755 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/GrAARectRenderer.cpp b/src/gpu/GrAARectRenderer.cpp
index e1abc31..ea15ce3 100644
--- a/src/gpu/GrAARectRenderer.cpp
+++ b/src/gpu/GrAARectRenderer.cpp
@@ -100,7 +100,7 @@
                     fsWidthHeightName);
 
             SkString modulate;
-            GrGLSLModulate4f(&modulate, inputColor, "coverage");
+            GrGLSLModulatef<4>(&modulate, inputColor, "coverage");
             builder->fsCodeAppendf("\t%s = %s;\n", outputColor, modulate.c_str());
         }