Google cast support with docs

[gelotte]

A very simple implementation of a cast sender application, for Chromecast and other receivers. The only working button in the control bar is the PlayToggle. This can serve as a base for further implementation of the components required by projects.

I made a CastPlayToggle component that wraps the regular PlayToggle so the easiest implementation is to disable the default controls and use this one instead. Another way is to let the CastPlayToggle handle only the "remote player" and switching between controls in the ControlBar component instead, i.e.

<PlayToggle disabled={this.state.isCasting} />
<CastPlayToggle disabled={!this.state.isCasting} />

Let me know if anyone has thoughts about other approaches to the local/remote player controls and state display.

[codecov-io]

Codecov Report

Merging #293 into master will increase coverage by 0.44%.
The diff coverage is 92.3%.

@@            Coverage Diff             @@
##           master     #293      +/-   ##
==========================================
+ Coverage   48.04%   48.48%   +0.44%     
==========================================
  Files          47       48       +1     
  Lines        1278     1291      +13     
==========================================
+ Hits          614      626      +12     
- Misses        664      665       +1

Impacted Files	Coverage Δ
src/components/control-bar/CastPlayToggle.js	92.3% <92.3%> (ø)

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[mondaychen]

Thank you for submitting such a high-quality PR! However, at this moment I don't think it's a good idea to add a component in video-react just for Google Cast since it's not widely used. Video-react is highly customizable at many levels, so users can add the feature to support Google Cast by creating their own components.

It will be nice if you can keep it a simple and clear doc page (like https://video-react.js.org/customize/customize-source/) demonstrating this use case.

[stolinski]

I respectfully disagree that Google Cast is not widely used. It's extremely popular and expected functionality.