Fixed Block Factory XML not Getting Properly Cleaned (#2801)

* Fixed factory XML not getting properly cleaned.

* Added jsdoc.

demos/blockfactory/factory_utils.js

@@ -921,12 +921,12 @@ FactoryUtils.sameBlockXml = function(blockXml1, blockXml2) {
   // Each XML element should contain a single child element with a 'block' tag
   if (blockXml1.tagName.toLowerCase() != 'xml' ||
       blockXml2.tagName.toLowerCase() != 'xml') {
-    throw new Error('Expected two XML elements, recieved elements with tag ' +
+    throw new Error('Expected two XML elements, received elements with tag ' +
         'names: ' + blockXml1.tagName + ' and ' + blockXml2.tagName + '.');
   }
 
   // Compare the block elements directly. The XML tags may include other meta
-  // information we want to igrore.
+  // information we want to ignore.
   var blockElement1 = blockXml1.getElementsByTagName('block')[0];
   var blockElement2 = blockXml2.getElementsByTagName('block')[0];
 
@@ -934,8 +934,11 @@ FactoryUtils.sameBlockXml = function(blockXml1, blockXml2) {
     throw new Error('Could not get find block element in XML.');
   }
 
-  var blockXmlText1 = Blockly.Xml.domToText(blockElement1);
+  var cleanBlockXml1 = FactoryUtils.cleanXml(blockElement1);
-  var blockXmlText2 = Blockly.Xml.domToText(blockElement2);
+  var cleanBlockXml2 = FactoryUtils.cleanXml(blockElement2);
+
+  var blockXmlText1 = Blockly.Xml.domToText(cleanBlockXml1);
+  var blockXmlText2 = Blockly.Xml.domToText(cleanBlockXml2);
 
   // Strip white space.
   blockXmlText1 = blockXmlText1.replace(/\s+/g, '');
@@ -945,6 +948,47 @@ FactoryUtils.sameBlockXml = function(blockXml1, blockXml2) {
   return blockXmlText1 == blockXmlText2;
 };
 
+/**
+ * Strips the provided xml of any attributes that don't describe the
+ * 'structure' of the blocks (i.e. block order, field values, etc).
+ * @param {Node} xml The xml to clean.
+ * @return {Node}
+ */
+FactoryUtils.cleanXml = function(xml) {
+  var newXml = xml.cloneNode(true);
+  var node = newXml;
+  while (node) {
+    // Things like text inside tags are still treated as nodes, but they
+    // don't have attributes (or the removeAttribute function) so we can
+    // skip removing attributes from them.
+    if (node.removeAttribute) {
+      node.removeAttribute('xmlns');
+      node.removeAttribute('x');
+      node.removeAttribute('y');
+      node.removeAttribute('id');
+    }
+
+    // Try to go down the tree
+    var nextNode = node.firstChild || node.nextSibling;
+    // If we can't go down, try to go back up the tree.
+    if (!nextNode) {
+      nextNode = node.parentNode;
+      while (nextNode) {
+        // We are valid again!
+        if (nextNode.nextSibling) {
+          nextNode = nextNode.nextSibling;
+          break;
+        }
+        // Try going up again. If parentNode is null that means we have
+        // reached the top, and we will break out of both loops.
+        nextNode = nextNode.parentNode;
+      }
+    }
+    node = nextNode;
+  }
+  return newXml;
+};
+
 /*
  * Checks if a block has a variable field. Blocks with variable fields cannot
  * be shadow blocks.