Combine leaks with same stacktrace

Combine similar leaks (those with identical stack traces) into a single
leak report, and sort the resulting leaks by total leak size across all
similar leaks and their references.

Bug: 27208635
Change-Id: Ia2bf2ccf3fcbc110d1c7ba60e3b77348d1c63d8d
diff --git a/libmemunreachable/LeakFolding.h b/libmemunreachable/LeakFolding.h
index 65e9916..732d3f2 100644
--- a/libmemunreachable/LeakFolding.h
+++ b/libmemunreachable/LeakFolding.h
@@ -33,7 +33,7 @@
     size_t referenced_size;
   };
 
-  bool Leaked(allocator::vector<Leak>& leaked, size_t limit,
+  bool Leaked(allocator::vector<Leak>& leaked,
       size_t* num_leaks_out, size_t* leak_bytes_out);
 
  private: