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">


const newRef = xref.getNewRef();
    const AP = new Dict(xref);
    AP.set("N", newRef);
    const encrypt = xref.encrypt;
    let originalTransform = null;
    let newTransform = null;
    if (encrypt) {
      originalTransform = encrypt.createCipherTransform(
        this.ref.num,
        this.ref.gen
      );
      newTransform = encrypt.createCipherTransform(newRef.num, newRef.gen);
      appearance = newTransform.encryptString(appearance);
    }
    dict.set("V", isAscii(value) ? value : stringToUTF16BEString(value));
    dict.set("AP", AP);
    dict.set("M", `D:${getModificationDate()}`);
    const appearanceDict = new Dict(xref);
    appearanceDict.set("Length", appearance.length);
    appearanceDict.set("Subtype", Name.get("Form"));
    appearanceDict.set("Resources", this._getSaveFieldResources(xref));
    appearanceDict.set("BBox", bbox);
    const bufferOriginal = [`${this.ref.num} ${this.ref.gen} obj\n`];
    writeDict(dict, bufferOriginal, originalTransform);
    bufferOriginal.push("\nendobj\n");
    const bufferNew = [`${newRef.num} ${newRef.gen} obj\n`];
    writeDict(appearanceDict, bufferNew, newTransform);
    bufferNew.push(" stream\n");
    bufferNew.push(appearance);
    bufferNew.push("\nendstream\nendobj\n");