Remove unused ExtraData support on exported mediastream objects.

Remove unused ExtraData support on exported mediastream objects.

The Blink exported interfaces RTCSessionDescriptionRequest, RTCVoidRequest,
and MediaStreamTrackSourcesRequest provide a facility to the embedder of
allowing 'ExtraData' to be associated and attached to object instances.

The embedder does not make use of this functionality for these mediastream objects,
so retire the unused ExtraData support. This simplifies the implementation of these
exported objects, in particular as regards to when they must be finalized as Blink
objects.

R=
BUG=

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=198741

[haraken, 2015-07-12 10:09:44]

haraken@chromium.org changed reviewers:
+ haraken@chromium.org

[haraken, 2015-07-12 10:09:45]

LGTM

[sof, 2015-07-12 13:46:30]

sigbjornf@opera.com changed reviewers:
+ tkent@chromium.org

[sof, 2015-07-12 13:46:31]

tkent@: agree that just retiring this extra from a public/ header is preferable?

(this came to the fore via https://codereview.chromium.org/1227533004/ )

[sof, 2015-07-12 14:18:52]

Let's extend this to also cover MediaStreamTrackSourcesRequest and
RTCVoidRequest, where this ExtraData functionality is unused also. Needed for
the other mediastream objects that provide this associative ExtraData.

(It just simplifies dependencies and finalization timing between Blink (Oilpan)
and the embedder; can be resurrected later on, if a need should arise.)

[haraken, 2015-07-12 16:12:53]

haraken@chromium.org changed reviewers:
+ tommi@chromium.org

[haraken, 2015-07-12 16:12:53]

Still LGTM but I want to have tommi confirm the change.

[sof, 2015-07-12 17:55:12]

On 2015/07/12 16:12:53, haraken wrote:
> Still LGTM but I want to have tommi confirm the change.

Thanks for the quick review.

Better have this pare down in functionality approved by a mediastream/ owner
also; tommyw is Cc:ed already.

[tommi (sloooow) - chröme, 2015-07-12 18:32:39]

lgtm

[tkent, 2015-07-12 23:30:13]

The CQ bit was checked by tkent@chromium.org

[tkent, 2015-07-12 23:30:14]

lgtm

[commit-bot: I haz the power, 2015-07-12 23:30:22]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1233793002/40001

[commit-bot: I haz the power, 2015-07-12 23:33:29]

Committed patchset #3 (id:40001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=198741