Fix position offset computing for window

[TrySound]

The case is visible when you scroll down 3000px, do small resize and scroll again. Viewport is cleaned. documentElement relativity is different.

[codecov-io]

Codecov Report

Merging #920 into master will increase coverage by 0.03%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #920      +/-   ##
==========================================
+ Coverage    89.9%   89.93%   +0.03%     
==========================================
  Files          57       57              
  Lines        1615     1620       +5     
==========================================
+ Hits         1452     1457       +5     
  Misses        163      163

Impacted Files	Coverage Δ
source/WindowScroller/utils/dimensions.js	100% <100%> (ø)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update f275a57...f325619. Read the comment docs.

[TrySound]

@bvaughn Tried to use puppeteer. There's a lot of boilerplate in installing and bootstrapping, but hope it can be resolved soon.

[TrySound]

Don't know how to fix it. Without sandboxing the error looks like this

Error: Failed to launch chrome!
/home/circleci/project/node_modules/puppeteer/.local-chromium/linux-515411/chrome-linux/chrome: error while loading shared libraries: libXcomposite.so.1: cannot open shared object file: No such file or directory


TROUBLESHOOTING: https://github.com/GoogleChrome/puppeteer/blob/master/docs/troubleshooting.md

    at onClose (/home/circleci/project/node_modules/puppeteer/lib/Launcher.js:211:14)
    at Interface.helper.addEventListener (/home/circleci/project/node_modules/puppeteer/lib/Launcher.js:200:50)
    at Interface.emit (events.js:164:20)
    at Interface.close (readline.js:381:8)
    at Socket.onend (readline.js:154:10)
    at Socket.emit (events.js:164:20)
    at endReadableNT (_stream_readable.js:1062:12)
    at process._tickCallback (internal/process/next_tick.js:152:19)

[TrySound]

I asked in local slack. Guys say all is good in travis.

[TrySound]

I'm gonna merge this and open PR with enabled e2e tests. Hope soon it will be merged :)

[bvaughn]

Hey Bogdan. Thanks for running with this. 😄

I've been spending time offline the past few days because I had family visiting from the East coast for the holidays. Happy to see you moved forward without being blocked.

[TrySound]

Happy holidays!