only read color array if flag is fixed color

Fixed color array shouldn't be required in Lattice
if no flag is set to kFixedColor.

Skip the read from the array if it is not set.

R=stani@google.com
Bug: skia:6898
Change-Id: I846b5fdf036cf110ce0ae4ffcf0654bca7029412
Reviewed-on: https://skia-review.googlesource.com/83942
Reviewed-by: Stan Iliev <stani@google.com>
Commit-Queue: Cary Clark <caryclark@skia.org>
diff --git a/src/core/SkLatticeIter.cpp b/src/core/SkLatticeIter.cpp
index 551982e..434cce6 100644
--- a/src/core/SkLatticeIter.cpp
+++ b/src/core/SkLatticeIter.cpp
@@ -192,7 +192,7 @@
                 }
 
                 fRectTypes[i] = *flags;
-                fColors[i] = *colors;
+                fColors[i] = SkCanvas::Lattice::kFixedColor == *flags ? *colors : 0;
                 flags++;
                 colors++;
                 i++;