Fix Issue #80 inserting every fontUsage (including unused font) for multiple html target

[palindrom615]

No description provided.

[coveralls]

Pull Request Test Coverage Report for Build 290

• 9 of 9 (100.0%) changed or added relevant lines in 1 file are covered.
• 2 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.2%) to 89.176%

---

Files with Coverage Reduction	New Missed Lines	%
lib/HeadlessBrowser.js	2	91.43%

Totals
Change from base Build 288:	-0.2%
Covered Lines:	979
Relevant Lines:	1050

---

💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 290

• 9 of 9 (100.0%) changed or added relevant lines in 1 file are covered.
• 2 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.2%) to 89.176%

---

Files with Coverage Reduction	New Missed Lines	%
lib/HeadlessBrowser.js	2	91.43%

Totals
Change from base Build 288:	-0.2%
Covered Lines:	979
Relevant Lines:	1050

---

💛 - Coveralls

[papandreou]

Thanks for the contribution, and sorry for the lack of feedback until now.

It's a bit hard to tell if it's a legit issue -- could you provide a failing test for the current state?

[papandreou]

This probably deserves to be its own test case alongside the existing one.

However, if I copy your test over to master, it also passes? Can you come up with an actual regression test?

[papandreou]

Mind turning this reduce construct into a regular for...of loop? I find those much easier to reason about.

[papandreou]

Hmm, mental note that we should find a better way achieve the "unique across pages" thing, sorting the output of _.uniq breaks when there's multiple non-UTF-16 characters:

require('lodash').uniq('🤗').sort().join('')
'🤗'
require('lodash').uniq('🤗🤞').sort().join('')
'🤗�'
require('lodash').uniq('🤗🤞👊').sort().join('')
'�🡊��'

[Munter]

This doesn't have the same problem. Not very readable though:

[...new Set([...'🤗🤞👊'])].sort().join('')

[papandreou]

Nice! I think we should go with that, then. Not readable is better than broken :)

[papandreou]

Implemented your fix here: #87

[papandreou]

Replaced by #111