Fix Windows compile error.

src/spaces.h

Index: src/spaces.h
diff --git a/src/spaces.h b/src/spaces.h
index dcb7769a50e58d1d62544fc807096fa550f3f0f4..855359835293d05bf7523a7a5b187d96a4ec7cbb 100644
--- a/src/spaces.h
+++ b/src/spaces.h
@@ -2017,7 +2017,7 @@ class PagedSpace : public Space {
   // If sweeping is still in progress try to sweep unswept pages. If that is
   // not successful, wait for the sweeper threads and re-try free-list
   // allocation.
-  MUST_USE_RESULT HeapObject* EnsureSweepingProgress(intptr_t size_in_bytes);
+  MUST_USE_RESULT HeapObject* EnsureSweepingProgress(int size_in_bytes);
 
   // Slow path of AllocateRaw.  This function is space-dependent.
   MUST_USE_RESULT HeapObject* SlowAllocateRaw(int size_in_bytes);