title: Uploading blob with FormData, File content is empty
body: <p>I'm trying to upload a blob with FormData on chrome.
  I'm building a web app.
  A user can create a profile and select an avatar, which is an img tag.
  When I'm trying to do an ajax request, I build a canvas with the image and call toDataURL on it.
  Then I transform the data into binary content using this function</p>
  
  <pre><code>    dataURItoBlob: function(dataURI) {
        var binary = atob(dataURI.split(',')[1]);
        var array = [];
        for(var i = 0; i &lt; binary.length; i++) {
          array.push(binary.charCodeAt(i));
        }
        return new Blob([new Uint8Array(array)], {type: 'application/octet-stream'});
      }
  </code></pre>
  
  <p>When the blob is created I add it to the formData and send the ajax query (with jquery).
  The thing is, the content of the file appears to be empty.</p>
  
  <pre><code> ------WebKitFormBoundarysToAVAYMLPFfJF96
   Content-Disposition: form-data; name="image"; filename="avatar.png"
   Content-Type: application/octet-stream
  
  
   ------WebKitFormBoundarysToAVAYMLPFfJF96--
  </code></pre>
  
  <p>Using FileReader I do a readAsText on the blob and it actually has content :</p>
  
  <pre><code> �PNG
  
  
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  </code></pre>
  
  <p>Has anyone already encountered this issue ?
  I just don't understand why the query sends an empty file.</p>