Add finer control of properties copied to subcollections

Memory.js

@@ -231,14 +231,8 @@ define([
 			});
 		},
 
-		_createSubCollection: function () {
-			var subCollection = this.inherited(arguments);
-
-			// Make sure a .data property is not carried over from this collection
-			// to corrupt the results of the new collection
-			subCollection.data = undefined;
-
-			return subCollection;
+		_includePropertyInSubCollection: function (name) {
+			return name !== 'data' && this.inherited(arguments);
 		}
 	});
 });

Store.js

@@ -220,14 +220,18 @@ define([
 			var newCollection = lang.delegate(this.constructor.prototype);
 
 			for (var i in this) {
-				if (!(i in newCollection) || newCollection[i] !== this[i]) {
+				if (this._includePropertyInSubCollection(i, newCollection)) {
 					newCollection[i] = this[i];
 				}
 			}
 
 			return declare.safeMixin(newCollection, kwArgs);
 		},
 
+		_includePropertyInSubCollection: function (name, subCollection) {
+			return !(name in subCollection) || subCollection[name] !== this[name];
+		},
+
 		// queryLog: __QueryLogEntry[]
 		//		The query operations represented by this collection
 		queryLog: [],	// NOTE: It's ok to define this on the prototype because the array instance is never modified