[heap] Make compaction space accept external memory.

src/heap/spaces-inl.h

Index: src/heap/spaces-inl.h
diff --git a/src/heap/spaces-inl.h b/src/heap/spaces-inl.h
index 762558e11bc6da131d4d6499972d06b1a13f594c..8dca9b198beaaf39c6b6256630b4fe37b1d7703c 100644
--- a/src/heap/spaces-inl.h
+++ b/src/heap/spaces-inl.h
@@ -356,6 +356,13 @@ AllocationResult PagedSpace::AllocateRawUnaligned(int size_in_bytes) {
 }
 
 
+AllocationResult PagedSpace::AllocateRawUnalignedSynchronized(
+    int size_in_bytes) {
+  base::LockGuard<base::Mutex> lock_guard(&space_mutex_);
+  return AllocateRawUnaligned(size_in_bytes);
+}
+
+
 // Raw allocation.
 AllocationResult PagedSpace::AllocateRawAligned(int size_in_bytes,
                                                 AllocationAlignment alignment) {