Clean up round and align in PartitionAlloc

Source/wtf/PartitionAlloc.h

Index: Source/wtf/PartitionAlloc.h
diff --git a/Source/wtf/PartitionAlloc.h b/Source/wtf/PartitionAlloc.h
index 1db9ab68245ce91cc9bd38dcd2886a8fc35b3603..57a20dcfac6ee3184ec6b6c8232d5f72474d93ad 100644
--- a/Source/wtf/PartitionAlloc.h
+++ b/Source/wtf/PartitionAlloc.h
@@ -726,13 +726,18 @@ ALWAYS_INLINE void partitionFreeGeneric(PartitionRootGeneric* root, void* ptr)
 #endif
 }
 
+ALWAYS_INLINE size_t partitionRoundUpToSystemPage(size_t size)
+{
+    return (size + kSystemPageOffsetMask) & kSystemPageBaseMask;
+}
+
 ALWAYS_INLINE size_t partitionDirectMapSize(size_t size)
 {
     // Caller must check that the size is not above the kGenericMaxDirectMapped
     // limit before calling. This also guards against integer overflow in the
     // calculation here.
     ASSERT(size <= kGenericMaxDirectMapped);
-    return (size + kSystemPageOffsetMask) & kSystemPageBaseMask;
+    return partitionRoundUpToSystemPage(size);
 }
 
 ALWAYS_INLINE size_t partitionAllocActualSize(PartitionRootGeneric* root, size_t size)