Replace uses of GR_DEBUGCODE by SkDEBUGCODE.

src/gpu/GrBlend.cpp

Index: src/gpu/GrBlend.cpp
diff --git a/src/gpu/GrBlend.cpp b/src/gpu/GrBlend.cpp
index 31e45fa57981e5f1245946d5f4db4d9bbb6ab081..c8631c42ef0d26c269d93705dbb2f909b57c6f11 100644
--- a/src/gpu/GrBlend.cpp
+++ b/src/gpu/GrBlend.cpp
@@ -113,7 +113,7 @@ static GrColor simplify_blend_term(GrBlendCoeff* srcCoeff,
             break;
     }
     // We may have invalidated these above and shouldn't read them again.
-    GR_DEBUGCODE(dstColor = constantColor = GrColor_ILLEGAL;)
+    SkDEBUGCODE(dstColor = constantColor = GrColor_ILLEGAL;)
 
     if (kZero_GrBlendCoeff == *srcCoeff || (valid_color(srcCompFlags) && 0 == srcColor)) {
         *srcCoeff = kZero_GrBlendCoeff;