Swizzle shader output and blend when using GL_RED to implement kAlpha_8_GrPixelConfig

src/gpu/gl/builders/GrGLProgramBuilder.h

Index: src/gpu/gl/builders/GrGLProgramBuilder.h
diff --git a/src/gpu/gl/builders/GrGLProgramBuilder.h b/src/gpu/gl/builders/GrGLProgramBuilder.h
index cbec5a9863539b125b75560ed6de8e5f55647782..70cfad5633ec652417cc6e42cae2b5c1e09f37c1 100644
--- a/src/gpu/gl/builders/GrGLProgramBuilder.h
+++ b/src/gpu/gl/builders/GrGLProgramBuilder.h
@@ -92,6 +92,7 @@ private:
                                 const GrGLSLExpr4& colorIn,
                                 const GrGLSLExpr4& coverageIn,
                                 bool ignoresCoverage);
+    void emitFSOutputSwizzle(bool hasSecondaryOutput);
 
     void verify(const GrPrimitiveProcessor&);
     void verify(const GrXferProcessor&);