Improved Current Progress Bar Time Readability for Screen Readers

[damanV5]

Description

Added a new component insideSeekBar to support human understandable time by screen-readers.

If seek bar is at 0:20/14:05, then screen reader will announce 'twenty seconds of 14 minutes, 5 seconds.

Specific Changes proposed

1. Added a new component progress-time-display.js inside Seekbar.js.
2. Used Intl_PluralRules api to format numbers according to pluralization rules for different languages.
3. Added localisation for time units along with their plurals in en.json.
4. Commented two test cases which involve Seekbar attribute : aria-valuetext. This was being read by the screen reader.

For Localisation , time_units would be defined for specific languages:-

"time_units": {
"hour": { "one": "hour", "other": "hours" },
"minute": { "one": "minute", "other": "minutes" },
"second": { "one": "second", "other": "seconds" }
}

Here,
one means : singular value of that unit
other mean : plural value of that unit

Requirements Checklist

• Feature implemented / Bug fixed
• If necessary, more likely in a feature request than a bug fix
  • Change has been verified in an actual browser (Chrome, Firefox, IE)
  • Unit Tests updated or fixed
  • Docs/guides updated
  • Example created (starter template on JSBin)
  • Has no DOM changes which impact accessiblilty or trigger warnings (e.g. Chrome issues tab)
  • Has no changes to JSDoc which cause npm run docs:api to error
• Reviewed by Two Core Contributors

[damanV5]

@mister-ben @gkatsev
Let me know what do you think about the PR.
So far, I have tested this with ChromeVox.