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">


this.data.defaultAppearance = "/Helvetica 0 Tf 0 g";
      this._defaultAppearanceData = parseDefaultAppearance(
        this.data.defaultAppearance
      );
    }
    const font = await this._getFontData(evaluator, task);
    const fontSize = this._computeFontSize(font, totalHeight);
    let descent = font.descent;
    if (isNaN(descent)) {
      descent = 0;
    }
    const vPadding = defaultPadding + Math.abs(descent) * fontSize;
    const defaultAppearance = this.data.defaultAppearance;
    const alignment = this.data.textAlignment;
    if (this.data.multiLine) {
      return this._getMultilineAppearance(
        defaultAppearance,
        value,
        font,
        fontSize,
        totalWidth,
        totalHeight,
        alignment,
        hPadding,
        vPadding
      );
    }