Add an option to calculate bandwidth by using Chromium's networkInfo API

[evanfarina]

Description

We've found that the player's bandwidth estimations provide lower-than-expected values when a particular segment is encoded with a low bitrate relative to other segments in its lane. This is a fairly common phenomenon when a live stream is using a variable bitrate encoding strategy and is broadcasting a static scene (e.g a slide in a slideshow). We believe that this issue is further exacerbated by two factors:

1. Segment size - Vhs estimates bandwidth by measuring how many bits were downloaded in a segment and how long, in seconds, it took to download those bits. This estimate factors in network-layer overhead which means that as the number of bits in a segment decreases (either due to bitrate or segment size), the impact that network overhead has on the bandwidth estimate increases
2. Bandwidth Variance config - Vhs uses a BANDWIDTH_VARIANCE value as a multiplier for the advertised bandwidth value in each lane. The filter calculation looks like lane bandwidth * bandwidth variance < calculatedBandwidth. When calculatedBandwidth is low due to aforementioned reasons, the bandwidth variance default makes it more likely that higher-quality lanes will be filtered out by the player

Specific Changes proposed

Introduce an experimental option that allows the player to leverage Chromium's NetworkInfo.downlink API to estimate bandwidth. Note: This API is not available in Firefox or Safari. When enabled, the player will take the max value between its own bandwidth estimation and that provided by NetworkInformation.downlink.

Please see attached screenshots which demonstrate how the player now selects the higher-quality rendition during static scenes. This demo uses 2-second segments.

## Requirements Checklist - [x] Feature implemented / Bug fixed - [ ] If necessary, more likely in a feature request than a bug fix - [ ] Unit Tests updated or fixed - [ ] Docs/guides updated - [ ] Example created ([starter template on JSBin](https://jsbin.com/gejugat/edit?html,output)) - [ ] Reviewed by Two Core Contributors

[codecov]

Codecov Report

Merging #1218 (8334564) into main (25c33ca) will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #1218      +/-   ##
==========================================
+ Coverage   86.42%   86.43%   +0.01%     
==========================================
  Files          39       39              
  Lines        9743     9752       +9     
  Branches     2263     2267       +4     
==========================================
+ Hits         8420     8429       +9     
  Misses       1323     1323              

Impacted Files	Coverage Δ
src/videojs-http-streaming.js	90.78% <100.00%> (+0.19%)	⬆️

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[gesinger]

Thank you for the PR @evanfarina ! A few comments for consideration.

[gkatsev]

It's nice that it's pretty simple and self-contained!