message: Add comments explaining our non standard usage of aria-described-by
diff: @@ -76,6 +76,12 @@ export default React.createClass({
  className={this.props.className}
  role="dialog"
  aria-labelledby='mx_BaseDialog_title'
  + // This should point to a node describing the dialog.
  + // If we were about to completelly follow this recommendation we'd need to
  + // make all the components relying on BaseDialog to be aware of it.
  + // So instead we will use the whole content as the description.
  + // Description comes first and if the content contains more text,
  + // AT users can skip its presentation.
  aria-describedby={this.props.contentId}
  >
  <AccessibleButton onClick={this._onCancelClick}
  