king the request.
              </dd>
              <dt id="overrideMimeType" class="callable">
                  <a href="polymer_app_layout/HttpRequest/overrideMimeType.html"><span class="name ">overrideMimeType</span></a><span class="signature">(<wbr><span class="parameter" id="overrideMimeType-param-override"><span class="type-annotation">String</span> <span class="parameter-name">override</span></span>)
                      &#8594;
                      <span class="returntype">void</span>
           