public int getMaxEms() {
    return mMaxWidthMode == EMS ? mMaxWidth : -1;
  }
Returns the max width expressed in ems.

@return the max width expressed in ems or -1, if max width is set in pixels instead
@see #setMaxEms(int)
library/src/main/java/com/facebook/fbui/textlayoutbuilder/TextLayoutBuilder.java