Attach (recommended) or Link to PDF file here: https://www.recom-power.com/pdf/Powerline-AC-DC/RAC05-K.pdf

Configuration:
- Web browser and its version: Firefox 56.0 (64-bit)
- Operating system and its version: Windows 10 with OS Build 15063.632
- PDF.js version: ?
- Is an extension: Built-in

Steps to reproduce the problem:
1. Open Page

What is the expected behavior? To properly render the first page. 
![image](https://user-images.githubusercontent.com/1151969/31415345-b1504022-add7-11e7-855b-8030a308f7a2.png)

What went wrong? Renders poorly.
![image](https://user-images.githubusercontent.com/1151969/31415363-d8842096-add7-11e7-818d-728c1102891b.png)

Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension): ?

if (width < measuredWidth && this.isFontSubpixelAAEnabled) {
          const characterScaleX = width / measuredWidth;
          restoreNeeded = true;
          ctx.save();
          ctx.scale(characterScaleX, 1);
          scaledX /= characterScaleX;
        } else if (width !== measuredWidth) {
          scaledX +=
            (((width - measuredWidth) / 2000) * fontSize) / fontSizeScale;
        }
      }
      
      
      if (this.contentVisible && (glyph.isInFont || font.missingFile)) {
        if (simpleFillText && !accent) {
          
          ctx.fillText(character, scaledX, scaledY);
        } else {
          this.paintChar(
            character,
            scaledX,
            scaledY,
            patternTransform,
            resetLineWidthToOne
          );
          if (accent) {
            const scaledAccentX =
              scaledX + (fontSize * accent.offset.x) / fontSizeScale;
            const scaledAccentY =
              scaledY - (fontSize * accent.offset.y) / fontSizeScale;