Changing Size to SizeOfObjects in GetHeapSpaceStatistics api.

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index 3a89095d0b7344512dbbd6658d816f09bd851322..5e868d3249850ba19054f2ab5cd0c5aad8ff9311 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -6892,7 +6892,7 @@ bool Isolate::GetHeapSpaceStatistics(HeapSpaceStatistics* space_statistics,
 
   space_statistics->space_name_ = heap->GetSpaceName(static_cast<int>(index));
   space_statistics->space_size_ = space->CommittedMemory();
-  space_statistics->space_used_size_ = space->Size();
+  space_statistics->space_used_size_ = space->SizeOfObjects();
   space_statistics->space_available_size_ = space->Available();
   space_statistics->physical_space_size_ = space->CommittedPhysicalMemory();
   return true;