As per internal feedback.
The `length` property exists if the `adsbygoogle` object
is instantiated before the `adsbygoogle.js` script has
been loaded, but is no longer present once the
`adsbygoogle.js` script has been loaded.
Related issue:
- https://github.com/uBlockOrigin/uBlock-issues/issues/786
A case of web page embedding multiple times the
`adsbygoogle.js` script was causing the neutered,
replacement script to create a huge amount of iframes
in the DOM.
The scriptlet has been modified to check if an iframe
tag already exist and skip the creation if so.
This is a first step, the ultimate goal is to remove
the need for resources.txt, or at least to reduce to
only hotfixes or for trivial resources targeting very
specific websites.
Most resources will become immutable, i.e. they will
be part of uBO's code base. Advantages include easier
code maintenance (jshint, syntax highlight), and to
make scriptlets more easy to code review by external
parties (for example extension store reviewers).
TODO:
- More scriptlets need to be imported before next
release.
- Need to make legacy versions of uBO use a legacy
version of resources.txt, as all the now obsolete
scriptlets will have to be removed once uBO's
next release become widespread.
- Possibly need to add code to load binary
resources so that they can be injected as
data: URI. So far it's unclear whether this is
really needed. For example, this would be needed
if a xmlhttprequest is redirected to an image
resource.
