Fix Win64 build breakage in r12082.

src/heap.cc

Index: src/heap.cc
diff --git a/src/heap.cc b/src/heap.cc
index 309d0adf02ae1310cf654b9b261ba7632f1f336f..9e38f513703521d30a3ee8fedfe56c3e774f062b 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -7216,17 +7216,19 @@ static LazyMutex checkpoint_object_stats_mutex = LAZY_MUTEX_INITIALIZER;
 void Heap::CheckpointObjectStats() {
   ScopedLock lock(checkpoint_object_stats_mutex.Pointer());
   Counters* counters = isolate()->counters();
-#define ADJUST_LAST_TIME_OBJECT_COUNT(name) \
-  counters->count_of_##name()->Increment(object_counts_[name]); \
-  counters->count_of_##name()->Decrement(object_counts_last_time_[name]); \
-  counters->size_of_##name()->Increment(object_sizes_[name]); \
-  counters->size_of_##name()->Decrement(object_sizes_last_time_[name]);
+#define ADJUST_LAST_TIME_OBJECT_COUNT(name)                                    \
+  counters->count_of_##name()->Increment(                                      \
+      static_cast<int>(object_counts_[name]));                                 \
+  counters->count_of_##name()->Decrement(                                      \
+      static_cast<int>(object_counts_last_time_[name]));                       \
+  counters->size_of_##name()->Increment(                                       \
+      static_cast<int>(object_sizes_[name]));                                  \
+  counters->size_of_##name()->Decrement(                                       \
+      static_cast<int>(object_sizes_last_time_[name]));
   INSTANCE_TYPE_LIST(ADJUST_LAST_TIME_OBJECT_COUNT)
 #undef ADJUST_LAST_TIME_OBJECT_COUNT
-  memcpy(object_counts_last_time_, object_counts_,
-         sizeof(object_counts_));
-  memcpy(object_sizes_last_time_, object_sizes_,
-         sizeof(object_sizes_));
+  memcpy(object_counts_last_time_, object_counts_, sizeof(object_counts_));
+  memcpy(object_sizes_last_time_, object_sizes_, sizeof(object_sizes_));
   ClearObjectStats();
 }