[heap] Use size_t throughout MemoryAllocator

src/extensions/statistics-extension.cc

Index: src/extensions/statistics-extension.cc
diff --git a/src/extensions/statistics-extension.cc b/src/extensions/statistics-extension.cc
index 53370206346bfa5d15ac4416acad8525a21175cb..da533363af57bd62ce7b05f3b23df99fef1e980c 100644
--- a/src/extensions/statistics-extension.cc
+++ b/src/extensions/statistics-extension.cc
@@ -117,7 +117,8 @@ void StatisticsExtension::GetCounters(
   };
 
   const StatisticNumber numbers[] = {
-      {heap->memory_allocator()->Size(), "total_committed_bytes"},
+      {static_cast<intptr_t>(heap->memory_allocator()->Size()),
+       "total_committed_bytes"},
       {heap->new_space()->Size(), "new_space_live_bytes"},
       {heap->new_space()->Available(), "new_space_available_bytes"},
       {static_cast<intptr_t>(heap->new_space()->CommittedMemory()),