Change default plot id and add initial div to DOM

Author: mdtusz

devtools/test_dashboard_v2/devtools.js

@@ -2,12 +2,12 @@
 var Tabs = {
 
     getGraph: function(id) {
-        id = id || 'default-plot';
+        id = id || 'graph';
         return document.getElementById(id);
     },
 
     fresh: function(id) {
-        id = id || 'default-plot';
+        id = id || 'graph';
 
         var graphDiv = Tabs.getGraph(id);
 

devtools/test_dashboard_v2/index.html

@@ -67,7 +67,9 @@
   </header>
 
   <section id="mocks-list"></section>
-  <div id="plots"></div>
+  <div id="plots">
+    <div id="graph"></div>
+  </div>
   <div id="snapshot"></div>
 
   <script id="source" type="text/javascript" src="../../build/plotly.js"></script>