Support $generichide adblock rules

[ryanbr]

Description

We should support $generichide and $ghide (ubo style) in Brave, bring us inline with uBO, ABP, Adguard and other adblockers. Generichide filter is used to counter sites against Anti-adblock measures for checking generic css divs.

Popularity (as of 22/03/2020)

uBO Filters.txt (1535 generichide/ghide lines):
grep \$ghide filters.txt | wc -l
1535

Easylist (295 $generichide lines):
grep -r generichide * | wc -l
295

How its implemented:

Sample domain filter:
@@||domain.com^$generchide

Cosmetics wouldn't apply to domain.com:
##.adblock
###adbanner
###ad_text:not(textarea)
###tads + div + .c
Cosmetic would apply:
domain.com##.topBarAd
domain.com###sidebar-ad
domain.com##a[href^="https://dltags.com/"]

Original Implementation:
https://adblockplus.org/development-builds/new-filter-options-generichide-and-genericblock

Steps to Reproduce

1. Visiting https://www.forbes.com
2. Expecting uBo filters.txt @@||forbes.com^$generichide to hide the generic filters the site is using.
3. See the work around: Hide generic elements on forbes.com adblock-lists#352

[LaurenWags]

Verified passed with

Brave | 1.12.92 Chromium: 84.0.4147.89 (Official Build) dev (64-bit)
-- | --
Revision | 19abfe7bcba9318a0b2a6bc6634a67fc834aa592-refs/branch-heads/4147@{#852}
OS | macOS Version 10.14.6 (Build 18G3020)

• Verified test plan from Support generichide adblock rules brave-core#5581

---

Verification passed on

Brave | 1.12.94 Chromium: 84.0.4147.89 (Official Build) dev (64-bit)
-- | --
Revision | 19abfe7bcba9318a0b2a6bc6634a67fc834aa592-refs/branch-heads/4147@{#852}
OS | Windows 10 OS Version 1903 (Build 18362.959)

• Verified test plan from Support generichide adblock rules brave-core#5581
  
  

---

Verification passed on

Brave	1.12.99 Chromium: 84.0.4147.89 (Official Build) dev (64-bit)
Revision	19abfe7bcba9318a0b2a6bc6634a67fc834aa592-refs/branch-heads/4147@{#852}
OS	Ubuntu 18.04 LTS

• Verified test plan from Support generichide adblock rules brave-core#5581

[srirambv]

Removing OS/Android label as there is no aggressive/standard setting available yet on Android.