Attach (recommended) or Link to PDF file here:
https://drive.google.com/open?id=1UjLxnFw2g3gn3tvNLRYLdmG6mFdFKCcr

Configuration:
- Web browser and its version: Chrome 77.0.3865.90
- Operating system and its version: Mac mojave 10.14.6
- PDF.js version: 2.3.194
- Is a browser extension: Nope

Steps to reproduce the problem:
1. Make sure to set `renderInteractiveForms` to `true`
2. The read-only form field(Sample title) doesn't honor it's proper font-size

What is the expected behavior?
<img width="862" alt="write" src="https://user-images.githubusercontent.com/4616548/66152094-4a009a80-e64b-11e9-81dc-178068055efa.png">

What went wrong?
<img width="842" alt="wrong" src="https://user-images.githubusercontent.com/4616548/66152100-4d942180-e64b-11e9-91a8-ad9caf451f98.png">


constructor(parameters) {
    super(parameters);
    this.data.annotationType = AnnotationType.POPUP;
    let parentItem = parameters.dict.get("Parent");
    if (!parentItem) {
      warn("Popup annotation has a missing or invalid parent annotation.");
      return;
    }
    const parentSubtype = parentItem.get("Subtype");
    this.data.parentType = isName(parentSubtype) ? parentSubtype.name : null;
    const rawParent = parameters.dict.getRaw("Parent");
    this.data.parentId = isRef(rawParent) ? rawParent.toString() : null;
    const parentRect = parentItem.getArray("Rect");
    if (Array.isArray(parentRect) && parentRect.length === 4) {
      this.data.parentRect = Util.normalizeRect(parentRect);
    } else {
      this.data.parentRect = [0, 0, 0, 0];
    }
    const rt = parentItem.get("RT");
    if (isName(rt, AnnotationReplyType.GROUP)) {