Update jpeg writer to compile on iOS and document it better

Update jpeg writer to compile on iOS and document it better

Original implementation of jpeg writer didn't compile on iOS at all.
This required clients to exclude some code using defines, which leads to 
more complicated code.

Now, instead, jpeg writer will compile but will do nothing on iOS. Clients'
code don't need any additional checks now.

BUG=none

Review-Url: https://codereview.webrtc.org/3004603002
Cr-Commit-Position: refs/heads/master@{#19558}
Committed: https://chromium.googlesource.com/external/webrtc/+/d986d768061f45a1d34ab8e97406ebcb6c15618a

[ilnik, 2017-08-28 07:46:09]

ilnik@webrtc.org changed reviewers:
+ kjellander@webrtc.org, sprang@webrtc.org

[sprang_webrtc, 2017-08-28 08:09:30]

lgtm but not a fan of the word "dummy". Maybe make it clear it's a null
implementation? Or mabye just call it jpeg_framewriter_ios so that if needed we
can implement a separate version there.

[ilnik, 2017-08-28 08:10:17]

On 2017/08/28 08:09:30, sprang_webrtc wrote:
> lgtm but not a fan of the word "dummy". Maybe make it clear it's a null
> implementation? Or mabye just call it jpeg_framewriter_ios so that if needed
we
> can implement a separate version there.

Good idea. Renaming it to "_ios".

[kjellander_webrtc, 2017-08-28 12:27:15]

lgtm but I'd like a little more background behind why this is done in the CL
description.

Is there a bug related to this work?

[ilnik, 2017-08-28 12:40:38]

On 2017/08/28 12:27:15, kjellander_webrtc wrote:
> lgtm but I'd like a little more background behind why this is done in the CL
> description.
> 
> Is there a bug related to this work?

No bug, just housekeeping. It was my mistake making this class non-compilable on
iOS. It needlessly complicates clients using it.
I'll update the description before committing.

[ilnik, 2017-08-28 12:42:24]

Description was changed from

==========
Update jpeg writer to compile on iOS and document it better

BUG=none
==========

to

==========
Update jpeg writer to compile on iOS and document it better

Original implementation of jpeg writer didn't compile on iOS at all.
This required clients to exclude some code using defines, which leads to 
more complicated code.

Now, instead, jpeg writer will compile but will do nothing on iOS. Clients'
code don't need any additional checks now.

BUG=none
==========

[ilnik, 2017-08-28 12:42:52]

The CQ bit was checked by ilnik@webrtc.org

[ilnik, 2017-08-28 12:42:52]

The patchset sent to the CQ was uploaded after l-g-t-m from sprang@webrtc.org
Link to the patchset: https://codereview.webrtc.org/3004603002/#ps100001 (title:
"Rename jpeg_frame_writer_dummy.cc to jpeg_frame_writer_ios.cc")

[commit-bot: I haz the power, 2017-08-28 12:43:01]

CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.webrtc.org/...

[commit-bot: I haz the power, 2017-08-28 13:08:34]

CQ is committing da patch.

Bot data: {"patchset_id": 100001, "attempt_start_ts": 1503924172031420,
"parent_rev": "b32aaf97bd73d16604e9e85221f2dbc4a9433e61", "commit_rev":
"d986d768061f45a1d34ab8e97406ebcb6c15618a"}

[commit-bot: I haz the power, 2017-08-28 13:08:41]

Description was changed from

==========
Update jpeg writer to compile on iOS and document it better

Original implementation of jpeg writer didn't compile on iOS at all.
This required clients to exclude some code using defines, which leads to 
more complicated code.

Now, instead, jpeg writer will compile but will do nothing on iOS. Clients'
code don't need any additional checks now.

BUG=none
==========

to

==========
Update jpeg writer to compile on iOS and document it better

Original implementation of jpeg writer didn't compile on iOS at all.
This required clients to exclude some code using defines, which leads to 
more complicated code.

Now, instead, jpeg writer will compile but will do nothing on iOS. Clients'
code don't need any additional checks now.

BUG=none

Review-Url: https://codereview.webrtc.org/3004603002
Cr-Commit-Position: refs/heads/master@{#19558}
Committed:
https://chromium.googlesource.com/external/webrtc/+/d986d768061f45a1d34ab8e97...
==========

[commit-bot: I haz the power, 2017-08-28 13:08:42]

Committed patchset #6 (id:100001) as
https://chromium.googlesource.com/external/webrtc/+/d986d768061f45a1d34ab8e97...