Link to PDF file (or attach file here):
https://issues.apache.org/jira/secure/attachment/12650283/000004_ShadingPatternTextPDF.pdf

Configuration:
- Web browser and its version: FF 51.0.1 32bit
- Operating system and its version: W7
- PDF.js version: latest

Steps to reproduce the problem:
display file

What is the expected behavior? (add screenshot)
![ok](https://cloud.githubusercontent.com/assets/6665575/23339534/5ff2de9c-fc25-11e6-837e-0fdaf81b4ca9.png)

What went wrong? (add screenshot)
![nok](https://cloud.githubusercontent.com/assets/6665575/23339536/63f7a37e-fc25-11e6-813c-cc218cc4def3.png)

possibly similar problem:
https://www.pdflib.com/fileadmin/pdflib/Cookbook/pdf/color_gradient.pdf (shaded text completely missing)
https://issues.apache.org/jira/secure/attachment/12630566/pslib-shading.pdf (page 4, part of text missing)
https://issues.apache.org/jira/secure/attachment/12652009/pattern-shading-2-4-idMatrix.pdf (some text missing)
https://issues.apache.org/jira/secure/attachment/12652010/pattern-shading-2-4-noMatrix.pdf (some text missing)

} else {
      
      scale = Util.singularValueDecompose2dScale(owner.baseTransform);
      if (this.matrix) {
        const matrixScale = Util.singularValueDecompose2dScale(this.matrix);
        scale = [scale[0] * matrixScale[0], scale[1] * matrixScale[1]];
      }
    }
    
    
    const temporaryPatternCanvas = this._createMeshCanvas(
      scale,
      shadingFill ? null : this._background,
      owner.cachedCanvases
    );
    if (!shadingFill) {
      ctx.setTransform.apply(ctx, owner.baseTransform);
      if (this.matrix) {
        ctx.transform.apply(ctx, this.matrix);
      }
    }
    ctx.translate(
      temporaryPatternCanvas.offsetX,
      temporaryPatternCanvas.offsetY
    );
    ctx.scale(temporaryPatternCanvas.scaleX, temporaryPatternCanvas.scaleY);
    return ctx.createPattern(temporaryPatternCanvas.canvas, "no-repeat");
  }
}
class DummyShadingPattern extends BaseShadingPattern {