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 matrix = [1, 0, 0, 1, 0, 0];
        const bbox = [
          0,
          0,
          this.data.rect[2] - this.data.rect[0],
          this.data.rect[3] - this.data.rect[1],
        ];
        const transform = getTransformMatrix(this.data.rect, bbox, matrix);
        operatorList.addOp(OPS.beginAnnotation, [
          this.data.rect,
          transform,
          matrix,
        ]);
        const stream = new StringStream(content);
        return evaluator
          .getOperatorList({
            stream,
            task,
            resources: this._fieldResources.mergedResources,
            operatorList,
          })
          .then(function () {
            operatorList.addOp(OPS.endAnnotation, []);
            return operatorList;
          });
      }
    );
  }
  async save(evaluator, task, annotationStorage) {