You will need to include the 'pdf.js' and 'compatibility' as well in your application,

You can include in "index.html" like a
Code:
<script src="{link to the script}"  ...
But I suggest to use app.json file for.

This is how pdfjs include looks like in app.json:

Code:
"js": [
    {
        "path": "sdk/sencha-touch.js"
    },
    {
        "path": "sdk/pdf.js/pdf.js"
    },
    {
        "path": "sdk/pdf.js/compatibility.js"
    }
]