Link to PDF file (or attach file here):
[RP_25884_V2_UEL Semi Finals 2016-17_concepts.pdf](https://github.com/mozilla/pdf.js/files/994423/RP_25884_V2_UEL.Semi.Finals.2016-17_concepts.pdf)

Configuration:
- Web browser and its version: Chrome 58, Firefox 53
- Operating system and its version: MacOS 10.11.6
- PDF.js version:
- Is an extension: No

Steps to reproduce the problem:
1.  View the file the file


What is the expected behavior? (add screenshot)
<img width="560" alt="screen shot 2017-05-11 at 2 06 36 pm" src="https://cloud.githubusercontent.com/assets/2474027/25971992/189f4ebe-3653-11e7-8847-c9011984cb8d.png">

What went wrong? (add screenshot)
Textlayer exists here but font fails to render. No warning in the console from what I can see. Maybe related to the gradient?

<img width="637" alt="screen shot 2017-05-11 at 2 06 20 pm" src="https://cloud.githubusercontent.com/assets/2474027/25971997/1b518cc6-3653-11e7-96c0-9a03ffcb7d6e.png">

Thanks!
* how these flags are being used:
 *  - ANY, DISPLAY, and PRINT are the normal rendering intents, note the
 *    `PDFPageProxy.{render, getOperatorList, getAnnotations}`-methods.
 *  - ANNOTATIONS_FORMS, ANNOTATIONS_STORAGE, ANNOTATIONS_DISABLE control which
 *    annotations are rendered onto the canvas (i.e. by being included in the
 *    operatorList), note the `PDFPageProxy.{render, getOperatorList}`-methods
 *    and their `annotationMode`-option.
 *  - OPLIST is used with the `PDFPageProxy.getOperatorList`-method, note the
 *    `OperatorList`-constructor (on the worker-thread).
 */
const RenderingIntentFlag = {
  ANY: 0x01,
  DISPLAY: 0x02,
  PRINT: 0x04,
  ANNOTATIONS_FORMS: 0x10,
  ANNOTATIONS_STORAGE: 0x20,
  ANNOTATIONS_DISABLE: 0x40,
  OPLIST: 0x100,
};
const AnnotationMode = {
  DISABLE: 0,
  ENABLE: 1,
  ENABLE_FORMS: 2,
  ENABLE_STORAGE: 3,
};
const PermissionFlag = {
  PRINT: 0x04,
  MODIFY_CONTENTS: 0x08,
  COPY: 0x10,
  MODIFY_ANNOTATIONS: 0x20,