Fix clear growth limit not working.

Fixed clear growth limit not working. I suspect this was causing
the amazon app out of memory error. Fixed the out of memory message
misattributing the reason for out of memory to being fragmentation.
Added more info to the out of memory exception message.

Change-Id: I28ad42968af27468ca43368620232cf22b5f4f13
diff --git a/src/heap.h b/src/heap.h
index a302405..68ee923 100644
--- a/src/heap.h
+++ b/src/heap.h
@@ -438,6 +438,7 @@
   const bool enforce_heap_growth_rate_;
 
   // Maximum size that the heap can reach.
+  size_t capacity_;
   size_t growth_limit_;
   size_t max_allowed_footprint_;