This patch implements the page label functionality in a similar way as Adobe Reader.
For documents with page labels, if a non-existent page label is entered we'll try to fallback to the page number instead.
The patch also includes a preference (`disablePageLabels`), to make it easy to opt-out of using page labels if the user/implementor so wishes.
The way that `get/set currentPageLabel` is implemented in `PDFViewer`, is as wrappers for the corresponding `get/set currentPageNumber` functions, since that seemed like the cleanest solution.
The page labels are purposely *only* added to the page controls in the viewer UI, and not stored in e.g. the `ViewHistory`. Since doing so would mean adding unnecessary code complexity, without any real added value, and would also mean delaying the inital loading of PDF documents.
Note that this patch will ignore page labels if they are identical to standard page numbering, since in this case displaying the page labels adds no value (but only UI noise). The reason for handling this case specially, is that in practice a surprising number of PDF files include "pointless" page labels.
Please note that this is a hack, but I think that it should be OK for now to atleast get the preference landed. Refer to the code comment for further information.
Re: issue 7584 and PR 7586.
This patch is the first step towards implementing support for
interactive forms (AcroForms). It makes it possible to render text
widget annotations exactly like Adobe Reader/Acrobat.
Everything we implement for AcroForms is disabled by default using a
preference, mainly because it is not ready to use yet, but has to
implemented in many steps to avoid complexity. The preference allows us
to work with the code while not exposing the behavior by default. Mainly
storing entered values and printing them is still absent, which would be
minimal requirements for enabling this by default.
Privacy policy: https://github.com/Rob--W/pdfjs-telemetry#privacy-policy
Unit tests (offline):
```
node test/chromium/test-telemetry.js
```
Server tests (requires that Nginx is installed):
```
git clone https://github.com/Rob--W/pdfjs-telemetry.git
cd pdfjs-telemetry/
python testserver.py TestHttp TestHttps
```
Integration test (extension + server):
- Build the extension
- Edit build/chromium/telemetry.js and remove the check for
chrome.runtime.id.
- Start Chrome (preferably a new profile):
chromium --user-data-dir=/tmp/pdftest --no-first-run
- Open chrome://net-internals#events
- Visit chrome://extensions and enable Developer mode.
- Load unpacked extension, select build/chromium.
- Go to the chrome://net-internals tab and filter on pdfjs.robwu.nl.
- Click on URL_REQUEST and verify that the server replied with 204.
- Reload the extension.
- Verify that chrome://net-internals did not contain a new log request.
