Replace OS::MemCopy with OS::MemMove (just as fast but more flexible).

src/heap.cc

Index: src/heap.cc
diff --git a/src/heap.cc b/src/heap.cc
index 3c88980a576e8bcfc689fb6f6c62cfd93ae8fffb..9fa2e69143e02da7c2e2bc58b58350813402e745 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -688,9 +688,9 @@ void Heap::MoveElements(FixedArray* array,
 
   ASSERT(array->map() != HEAP->fixed_cow_array_map());
   Object** dst_objects = array->data_start() + dst_index;
-  memmove(dst_objects,
-          array->data_start() + src_index,
-          len * kPointerSize);
+  OS::MemMove(dst_objects,
+              array->data_start() + src_index,
+              len * kPointerSize);
   if (!InNewSpace(array)) {
     for (int i = 0; i < len; i++) {
       // TODO(hpayer): check store buffer for entries
@@ -4965,7 +4965,7 @@ static inline void WriteOneByteData(Vector<const char> vector,
                                     int len) {
   // Only works for ascii.
   ASSERT(vector.length() == len);
-  memcpy(chars, vector.start(), len);
+  OS::MemCopy(chars, vector.start(), len);
 }
 
 static inline void WriteTwoByteData(Vector<const char> vector,
@@ -7841,8 +7841,8 @@ void Heap::CheckpointObjectStats() {
   FIXED_ARRAY_SUB_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_));
+  OS::MemCopy(object_counts_last_time_, object_counts_, sizeof(object_counts_));
+  OS::MemCopy(object_sizes_last_time_, object_sizes_, sizeof(object_sizes_));
   ClearObjectStats();
 }