DM: wire up --leaks / -l again

dm/DM.cpp

Index: dm/DM.cpp
diff --git a/dm/DM.cpp b/dm/DM.cpp
index c8d1ec7f671827dc7ab7f7f6a42f03825e55ef65..faee2ccb1b64538e6f70df785efef8f924934811 100644
--- a/dm/DM.cpp
+++ b/dm/DM.cpp
@@ -8,6 +8,7 @@
 #include "SkCommonFlags.h"
 #include "SkForceLinking.h"
 #include "SkGraphics.h"
+#include "SkInstCnt.h"
 #include "SkMD5.h"
 #include "SkOSFile.h"
 #include "SkTDynamicHash.h"
@@ -490,6 +491,9 @@ int dm_main() {
     SetupCrashHandler();
     SkAutoGraphics ag;
     SkTaskGroup::Enabler enabled(FLAGS_threads);
+    if (FLAGS_leaks) {
+        SkInstCountPrintLeaksOnExit();
+    }
 
     gather_gold();