Resubmission of native memory allocation info surfacing in Observatory. Fixed crashing tests and st…

runtime/vm/malloc_hooks.h

Index: runtime/vm/malloc_hooks.h
diff --git a/runtime/vm/malloc_hooks.h b/runtime/vm/malloc_hooks.h
index 64e423dfed9688ec2e0335815c25d371199bca11..bea2f39fbeb863d8cbda3451b4297050b5b8f683 100644
--- a/runtime/vm/malloc_hooks.h
+++ b/runtime/vm/malloc_hooks.h
@@ -13,6 +13,14 @@ namespace dart {
 class JSONObject;
 class Sample;
 
+// The number of frames that are generated by the malloc hooks and collection
+// of the stack trace. These frames are ignored when collecting the stack
+// trace for a memory allocation. If this number is incorrect, some tests in
+// malloc_hook_tests.cc might fail, particularily
+// StackTraceMallocHookLengthTest. If this value is updated, please make sure
+// that the MallocHooks test cases pass on all platforms.
+extern const intptr_t kSkipCount;
+
 class MallocHooks : public AllStatic {
  public:
   static void InitOnce();