Link to PDF file (or attach file here):
[pages4.pdf](https://github.com/mozilla/pdf.js/files/1128300/pages4.pdf)

Configuration:
- Web browser and its version: Firefox 54
- Operating system and its version: Win 10
- PDF.js version: 1.8.522
- Is an extension: no

What is the expected behavior? (add screenshot)
![chrome1-1 1](https://user-images.githubusercontent.com/146436/27918380-2f74512a-6245-11e7-8525-d0038fa6c2e8.jpg)
![chrome1-2 1](https://user-images.githubusercontent.com/146436/27918425-54f8e47e-6245-11e7-9bff-127f79ad0511.jpg)


What went wrong? (add screenshot)
![screenshot from 2017-07-06 12-10-30](https://user-images.githubusercontent.com/146436/27918442-5d57624e-6245-11e7-9436-5ba31cc8bd1a.png)
![screenshot from 2017-07-06 12-10-44](https://user-images.githubusercontent.com/146436/27918454-63b486da-6245-11e7-9eb5-c03aa5c40943.png)



constructor(maxSize = 0) {
    this._cache = new Map();
    this._maxSize = maxSize;
  }
  has(key) {
    return this._cache.has(key);
  }
  get(key) {
    if (this._cache.has(key)) {
      
      const value = this._cache.get(key);
      this._cache.delete(key);
      this._cache.set(key, value);
    }
    return this._cache.get(key);
  }
  set(key, value) {
    if (this._maxSize <= 0) {
      return;
    }
    if (this._cache.size + 1 > this._maxSize) {
      
      this._cache.delete(this._cache.keys().next().value);
    }
    this._cache.set(key, value);
  }
  clear() {