Use the same type as mAttrAndChildCount when defining ATTRCHILD_ARRAY_MAX_CHILD_COUNT. b=480655 r+sr=jonas

content/base/src/nsAttrAndChildArray.h

@@ -64,7 +64,7 @@ class nsMappedAttributeElement;
     ((1 << ATTRCHILD_ARRAY_ATTR_SLOTS_BITS) - 1)
 
 #define ATTRCHILD_ARRAY_MAX_CHILD_COUNT \
-    (~PtrBits(0) >> ATTRCHILD_ARRAY_ATTR_SLOTS_BITS)
+    (~PRUint32(0) >> ATTRCHILD_ARRAY_ATTR_SLOTS_BITS)
 
 #define ATTRCHILD_ARRAY_ATTR_SLOTS_COUNT_MASK \
     ((1 << ATTRCHILD_ARRAY_ATTR_SLOTS_BITS) - 1)