Move the change block to the variables category

blocks/math.js

@@ -325,7 +325,7 @@ Blockly.Blocks['math_change'] = {
       ],
       "previousStatement": null,
       "nextStatement": null,
-      "colour": Blockly.Blocks.math.HUE,
+      "colour": Blockly.Blocks.variables.HUE,
       "helpUrl": Blockly.Msg.MATH_CHANGE_HELPURL
     });
     // Assign 'this' to a variable for use in the tooltip closure below.

core/variables.js

@@ -117,14 +117,43 @@ Blockly.Variables.flyoutCategory = function(workspace) {
     // </block>
     var block = goog.dom.createDom('block');
     block.setAttribute('type', 'variables_set');
-    if (Blockly.Blocks['variables_get']) {
-      block.setAttribute('gap', 20);
+    if (Blockly.Blocks['math_change']) {
+      block.setAttribute('gap', 8);
+    } else {
+      block.setAttribute('gap', 24);
     }
     var field = goog.dom.createDom('field', null, variableList[0]);
     field.setAttribute('name', 'VAR');
     block.appendChild(field);
     xmlList.push(block);
   }
+  if (Blockly.Blocks['math_change']) {
+    // <block type="math_change">
+    //   <value name="DELTA">
+    //     <shadow type="math_number">
+    //       <field name="NUM">1</field>
+    //     </shadow>
+    //   </value>
+    // </block>
+    var block = goog.dom.createDom('block');
+    block.setAttribute('type', 'math_change');
+    if (Blockly.Blocks['variables_get']) {
+      block.setAttribute('gap', 20);
+    }
+    var value = goog.dom.createDom('value');
+    value.setAttribute('name', 'DELTA');
+    block.appendChild(value);
+
+    var shadowBlock = goog.dom.createDom('shadow');
+    shadowBlock.setAttribute('type', 'math_number');
+    value.appendChild(shadowBlock);
+
+    var field = goog.dom.createDom('field', null, '1');
+    field.setAttribute('name', 'NUM');
+    shadowBlock.appendChild(field);
+
+    xmlList.push(block);
+  }
 
   for (var i = 0; i < variableList.length; i++) {
     if (Blockly.Blocks['variables_get']) {

tests/playground.html

@@ -472,13 +472,6 @@ h1 {
           </shadow>
         </value>
       </block>
-      <block type="math_change">
-        <value name="DELTA">
-          <shadow type="math_number">
-            <field name="NUM">1</field>
-          </shadow>
-        </value>
-      </block>
       <block type="math_round">
         <value name="NUM">
           <shadow type="math_number">