Suppression for valgrind bug

TBR=msarett@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

BUG=skia:4478

Review URL: https://codereview.chromium.org/1410953002
diff --git a/tools/valgrind.supp b/tools/valgrind.supp
index ffb7108..154a8a7 100644
--- a/tools/valgrind.supp
+++ b/tools/valgrind.supp
@@ -236,3 +236,15 @@
     Memcheck:Addr2
     fun:_ZN22GrAAConvexPathRenderer10onDrawPathERK6SkPathRK11SkStrokeRecP12GrDrawTargetb
 }
+#FIXME (scroggo). skbug.com/4478
+{
+   subset_translate_bench_skbug_4478
+   Memcheck:Leak
+   match-leak-kinds: definite
+   fun:_Znwm
+   fun:_ZN20SubsetTranslateBench6onDrawEiP8SkCanvas
+   fun:_ZN9Benchmark4drawEiP8SkCanvas
+   fun:_ZL4timeiP9BenchmarkP6Target
+   fun:_Z14nanobench_mainv
+   fun:main
+}