Remove the logic for de-duplicating in-band text track cues

Remove the logic for de-duplicating in-band text track cues

To de-duplicate cues by comparing their properties cannot work, since
scripts can modify cues in small or big ways at any time. For example,
the de-duplication will fail if the id has changed or if the timings
have been slightly shifted.

It must be the demuxer's responsibility to do this, e.g. by keeping
track of the offsets for which cues have already been sourced. This need
not consume a lot of memory, since it could record ranges of offsets.

BUG=270340
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=162245

[philipj_slow, 2013-11-16 15:49:33]

PTAL. Matthew, do you agree with my assessment that this agree can and should be
moved out to Chromium? If this really is something that Blink should do, then I
think that passing a unique identifier, hidden from scripts, would be a better
approach.

[philipj_slow, 2013-11-16 15:55:29]

https://codereview.chromium.org/23702007/ is the review that would have to adapt
to these changes.

[Matthew Heaney (Chromium), 2013-11-17 01:28:55]

lgtm

[philipj_slow, 2013-11-18 21:35:33]

Adam, LGTY?

[adamk, 2013-11-18 21:37:45]

lgtm rs=me for OWNERS (deferring to Matthew and Philip's judgments).

[adamk, 2013-11-18 21:38:09]

Though I'm curious why this didn't affect any tests

[philipj_slow, 2013-11-18 22:14:20]

On 2013/11/18 21:38:09, adamk wrote:
> Though I'm curious why this didn't affect any tests

It's because the platform side for in-band tracks hasn't actually landed yet,
see the review linked to in comment 2.

[commit-bot: I haz the power, 2013-11-18 22:20:47]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/philipj@opera.com/74623002/30004

[commit-bot: I haz the power, 2013-11-18 23:18:55]

Change committed as 162245