Issue 6504 - Remove element hiding emulation code related to style sheets

It turns out this is dead code now. We can remove it. If we ever get around to using style sheets properly, we can add it back.

[Manish Jethani, 2018-09-18 17:38:57]

Patch Set 1

[Sebastian Noack, 2018-09-18 21:29:47]

https://codereview.adblockplus.org/29884580/diff/29884581/lib/content/elemHid...
File lib/content/elemHideEmulation.js (left):

https://codereview.adblockplus.org/29884580/diff/29884581/lib/content/elemHid...
lib/content/elemHideEmulation.js:608: constructor(addSelectorsFunc,
hideElemsFunc)
There are further optimizations and simplifications we can do in
adblockpluschrome if we no longer have to provide an addSelectorFunc. On the
other hand, if you plan on bringing back user stylesheets for emulated element
hiding filters (?), I agree to keep the constructor backwards compatible and not
touch the related code in adblockpluschrome. But then you might want to add a
comment about that here.

[Manish Jethani, 2018-09-19 09:43:32]

https://codereview.adblockplus.org/29884580/diff/29884581/lib/content/elemHid...
File lib/content/elemHideEmulation.js (left):

https://codereview.adblockplus.org/29884580/diff/29884581/lib/content/elemHid...
lib/content/elemHideEmulation.js:608: constructor(addSelectorsFunc,
hideElemsFunc)
On 2018/09/18 21:29:47, Sebastian Noack wrote:
> There are further optimizations and simplifications we can do in
> adblockpluschrome if we no longer have to provide an addSelectorFunc. On the
> other hand, if you plan on bringing back user stylesheets for emulated element
> hiding filters (?), I agree to keep the constructor backwards compatible and
not
> touch the related code in adblockpluschrome. But then you might want to add a
> comment about that here.

At this point I'm really not sure how this is going to go. I would really like
to use style sheets, simply because it's cleaner and harder to mess with (some
documents go into a race condition because they try to unset the inline style
while we try to reset it); but it requires that we maintain the selectors and
keep them up to date, which is a lot of code. For now, I think I'll just leave a
comment in the constructor here. The full discussion about what to do in the
long run can continue on the Trac issue.

[Manish Jethani, 2018-09-19 13:25:51]

Patch Set 2: Add comment in constructor

By the way, why not use this opportunity to move to using named arguments?

  constructor({addSelectorsFunc, hideElemsFunc} = {})

[Manish Jethani, 2018-09-29 01:07:46]

Patch Set 3: Remove first parameter to constructor

[Sebastian Noack, 2018-09-29 01:14:37]

LGTM.

Respectively, https://codereview.adblockplus.org/29894564/ should no longer pass
in that argument, and should be turned into a dependency update.