code: function getNaturalDimensions (element) {
    let tagName = element.tagName.toLowerCase()
    if (!NATURAL_DIMENSIONS[tagName]) {
      let doc = element.ownerDocument
      let naturalTagName = tagName.replace(/^mip-/, '')
      let temp = doc.createElement(naturalTagName)
      // For audio, should no-op elsewhere.
      temp.controls = true
      temp.style.position = 'absolute'
      temp.style.visibility = 'hidden'
      doc.body.appendChild(temp)
      NATURAL_DIMENSIONS[tagName] = {
        width: (temp.offsetWidth || 1) + 'px',
        height: (temp.offsetHeight || 1) + 'px'
      }
      doc.body.removeChild(temp)
    }
    return NATURAL_DIMENSIONS[tagName]
  }
docs: Determines the default dimensions for an element which could lety across
  different browser implementations, like <audio> for instance.
  This operation can only be completed for an element whitelisted by
  `hasNaturalDimensions`.
  
  @param {!Element} element html element
  @return {DimensionsDef}