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">


{ x: maxX, y: maxY },
      { x: minX, y: minY },
      { x: maxX, y: minY },
    ];
  });
}
function getTransformMatrix(rect, bbox, matrix) {
  
  const [minX, minY, maxX, maxY] = Util.getAxialAlignedBoundingBox(
    bbox,
    matrix
  );
  if (minX === maxX || minY === maxY) {
    
    
    return [1, 0, 0, 1, rect[0], rect[1]];
  }
  const xRatio = (rect[2] - rect[0]) / (maxX - minX);
  const yRatio = (rect[3] - rect[1]) / (maxY - minY);
  return [
    xRatio,
    0,
    0,
    yRatio,
    rect[0] - minX * xRatio,
    rect[1] - minY * yRatio,
  ];
}
class Annotation {
  constructor(params) {