[STRATCONN-272, STRATCONN-265] Update trackComplete, Stringify context data, Support window-based playhead

[kdaswani]

https://segment.atlassian.net/browse/CC-6682

What does this PR do?

• Removes trackComplete from Video Content Completed events and only calls chapterComplete on these events. It also adds trackComplete to Video Playback Completed events. This is in line with Adobe's documentation and also allows for parity between iOS, a.js, and Android.
• Stringifies context data values which are booleans. The AA SDK tends to reject false boolean values when setting them on the window object. This does not break existing behavior since booleans are stringified when they're sent in the query string.
• Reads session playhead values from window._segHBPlayheads if it exists. This solves an issue where the playhead is only updated when Video Content Playing (+ various others) events are tracked. To get around this, we allow video implementations to set the playhead value as often as possible without the need to trigger an event. Adobe Analytics expects the playhead to be updated at least every second.

Note: It does not seem like we pause the playhead ever in the a.js integration so I did not add this to Video Playback Completed.

Are there breaking changes in this PR?
No.

Is there parity with the server-side/android/iOS integration components (if applicable)?
iOS and a.js integrations are being updated with the same changes.

Does this require a new integration setting? If so, please explain how the new setting works
No.

Links to helpful docs and other external resources
Adobe docs
Core playback on Android: https://docs.adobe.com/content/help/en/media-analytics/using/sdk-implement/track-av-playback/track-core/track-core-javascript/track-core-js3.html
Chapters on Android: https://docs.adobe.com/content/help/en/media-analytics/using/sdk-implement/track-chapters/track-chapters-js/track-chapters-js3.html

[gpsamson]

Merged in #473 since only one version can be pinned to a source at a time.

[briemcnally]

@gpsamson I just pulled this and tested with compiler.I passed video_genre: true and video_genre: video_genre in my contextValues in settings. It looks like false values are dropped whether or not they are stringified:

http://exchangepartnersegment.sc.omtrdc.net/b/ss/sgmbrietest/1/JS-2.20.0/s39562923460904?AQB=1&pccr=true&ndh=1&pf=1&t=29%2F5%2F2020%2016%3A55%3A52%201%20420&ts=2020-06-29T23%3A55%3A52.530Z&fid=20BABEE0B555DE7B-3E3F6227ACE3F571&ce=UTF-8&pageName=hello&g=http%3A%2F%2Flocalhost%3A3000%2F&c.&name=hello&path=%2F&url=http%3A%2F%2Flocalhost%3A3000%2F&.c&events=hello&s=1440x900&c=30&j=1.6&v=N&k=Y&bw=1440&bh=687&lrt=102&AQE=1

[gpsamson]

@briemcnally. That's odd. An event with video_genre: false is getting appended correctly for me:

http://exchangepartnersegment.sc.omtrdc.net/b/ss/sgmtest/1/JS-2.20.0/s44858310890909?AQB=1&ndh=1&pf=1&t=29%2F5%2F2020%2017%3A0%3A59%201%20420&ts=2020-06-30T00%3A00%3A59.700Z&mid=14465157012152281642777866379740413748&ce=UTF-8&pageName=AJS%20Testing%20Boilerplate&g=http%3A%2F%2Flocalhost%3A9000%2F&c.&url=http%3A%2F%2Flocalhost%3A9000%2F&video_genre=false&.c&events=event21&pe=lnk_o&pev2=CC&s=1680x1050&c=30&j=1.6&v=N&k=Y&bw=1439&bh=916&mcorgid=1234567ABC%40AdobeOrg&AQE=1

My context settings has video_genre: video_genre set and my a,.js call looks like:

  analytics.track('CC', {}, {
    video_genre: false
  })

The same is also true when the value is set to true.

[briemcnally]

🤔 Wonder why it didn't work for me. I'll try it again later.