remove SkInstCnt

It's been outclassed by Valgrind and leak sanitizer,
and it seems to be causing problems for external folks building Skia.

I'm not sure why our own builds seem unaffected.

Latest thread:
https://groups.google.com/forum/#!topic/skia-discuss/oj9FsQwwSF0

BUG=skia:

Review URL: https://codereview.chromium.org/1217573002

1 files changed, 0 insertions, 2 deletions

diff --git a/bench/Benchmark.h b/bench/Benchmark.h
index 30ceb88acb..34ea92b4a2 100644
--- a/bench/Benchmark.h
+++ b/bench/Benchmark.h
@@ -43,8 +43,6 @@ public:
 
 class Benchmark : public SkRefCnt {
 public:
-    SK_DECLARE_INST_COUNT(Benchmark)
-
     Benchmark();
 
     const char* getName();