Hello

I was wondering if PDF.js has a way to cancel or reject already created promises. We have documents that do not seem to load sequentially in the viewer.

Expected Behavior

1. Open Document A
2. Before Document A loads, Open Document B
3. Document B appears on screen

Steps to Reproduce

1. Load pdf.js viewer, which defaults to Document A (compressed.tracemonkey.pdf)
2. Open Document B (see attached Hello World.pdf)
3. Briefly, Docuemnt B appears
4. Document A (compressed.tracemonkey.pdf) appears on top of the Document B

Example

A sample file & video loaded in pdf.js viewer:

• HelloWorld.pdf: http://cl.ly/0i2N250G3z2I
• HelloWorld.m4v: http://cl.ly/3w0g1r2l2v3r

Investigation

In viewer.js:

• The 'Open' event seems to overwrite the PDFView by calling close on the prior document. The prior document's promises are not canceled
• In the example, Document B's load event seems to finish before the first Document A's load event does, and Document A's load / render promises overwrite the canvas