title: ChartJS 2.7.0 updating and exporting as png
body: <p>So I have a ChartJS chart and I am trying to update the title of this chart, thus far I have made it work and display the new title! (woohoo).</p>
  
  <p>However my issue comes when I try to export the chart with its new title showing. </p>
  
  <p>I am converting to a base64 png. Creating an a-tag, programatically clicking the a-tag, then removing the a-tag and finally changing the title back to the old title.</p>
  
  <p>Up to the point where I am trying to save the chart with new title as a base64 png everything works. Then the new title is not on the exported .png</p>
  
  <pre><code>function downloadImage($id) {
  console.log("");
  console.log("*///// SAVING /////*");
  
  //get the charts variable name (stored as a data-attribute on the canvas element called chart-var)
  var chart_variable_name = $("#" + $id).data('chart-var');
  //convert this to a usable variable instead of a string
  var chart_variable = eval(chart_variable_name);
  
  console.log("");
  console.log("Get Chart Variable");
  console.log(chart_variable);
  
  //get canvas element using id passed in
  var ctx = $("#" + $id);
  //get data-export-title attribute (multiline title with Title, Date, Source)
  var exportTitle = $(ctx).data('export-title');
  
  console.log("");
  console.log("Get Chart");
  console.log(ctx);
  
  console.log("");
  console.log("Get Chart Export Title");
  console.log(exportTitle);
  
  //get the old title from the ChartJS Object (ready to use for going back to old title)
  var old_title = chart_variable.options.title.text;
  
  console.log("");
  console.log("Get Chart Old Title");
  console.log(old_title);
  
  // get the exportTitle as an array, this will allow for MultiLine titles on export
  arr = exportTitle.split(',');
  
  console.log("");
  console.log("Get Chart New Title");
  console.log(arr);
  
  //push String "Title" + old_title variable so we have the title added at the end of the array
  arr.push("Title: " + old_title);
  
  //set the charts title text to the new Multiline export title.
  chart_variable.options.title.text = arr;
  
  //run the update on the chart
  chart_variable.update();
  
  chart_variable = eval(chart_variable_name);
  
  console.log("");
  console.log("Get Chart Current Options");
  console.log(chart_variable.options);
  
  //convert the chart to a base64 link PNG
  var newBase64 = chart_variable.toBase64Image();
  
  //insert an &lt;a&gt; tag which is hidden, before the save button - irrelevant where it goes as it wont be seen but for consistency
  $("&lt;a id='" + $id + "-button-temp' style='display:none;' class='button-style' href='" + newBase64 + "' download='" + $id + ".png' &gt;Download&lt;/a&gt;").insertAfter($('#' + $id + '-button'));
  
      //programmatically find and click the &lt;a&gt; tag to initiate the download of the image
     ($(document).find("#" + $id + "-button-temp")[0]).click();
  
     //programmatically remove the &lt;a&gt; tag so we dont clutter the page with unecessary HTML that are hidden
     ($(document).find("#" + $id + "-button-temp")[0]).remove();
  
     //set chart title back to previous title
    //chart_variable.options.title.text = old_title;
  }
  </code></pre>
  
  <p>Does anyone have an idea as to why this is happening...?</p>