This removes the `PDFJS.externalLinkTarget`/`PDFJS.externalLinkRel` dependency from the viewer components, but please note that as a *temporary* solution the default viewer still uses it.
These were removed in PR 9170, since they were unused in the browsers that we'll support in PDF.js version `2.0`.
However looking at the output of Travis, where a subset of the unit-tests are run using Node.js, there's warnings about `btoa` being undefined. This doesn't appear to cause any errors, which probably explains why we didn't notice this before (despite PR 9201).
This patch provides a new unit tested factory for creating SVG
containers and elements. This code is duplicated twice in the
codebase, but with upcoming changes this would need to be duplicated
even more. Moreover, consolidating this code in one factory allows
us to replace it easily for e.g., supporting Node.js. Therefore, move
this to a central place and update/ES6-ify the related code.
Finally, we replace `setAttributeNS` with `setAttribute` because no
namespace is provided.
