Reland of Add Metal video view in AppRTCMobile and metal availability macro.

Reland of Add Metal video view in AppRTCMobile and metal availability macro. (patchset #1 id:1 of https://codereview.webrtc.org/2739793003/ )

Reason for revert:
Fixing rendering issues in AppRTCMobile

Original issue's description:
> Revert of Add Metal video view in AppRTCMobile and metal availability macro. (patchset #5 id:80001 of https://codereview.webrtc.org/2722583002/ )
> 
> Reason for revert:
> Breaks AppRTCMobile
> 
> Original issue's description:
> > Add Metal video view in AppRTCMobile and Metal availability macro.
> > 
> > - The RTC_SUPPORTS_METAL macro allows consumers to gracefully handle compilation for different archs that are not supporting Metal.
> > 
> > BUG=webrtc:7079
> > 
> > Review-Url: https://codereview.webrtc.org/2722583002
> > Cr-Commit-Position: refs/heads/master@{#17004}
> > Committed: https://chromium.googlesource.com/external/webrtc/+/154a7bb877abefada22afe28b0a755cf621e8d9e
> 
> TBR=magjed@webrtc.org,tkchin@webrtc.org,denicija@webrtc.org
> # Not skipping CQ checks because original CL landed more than 1 days ago.
> BUG=webrtc:7079
> 
> Review-Url: https://codereview.webrtc.org/2739793003
> Cr-Commit-Position: refs/heads/master@{#17119}
> Committed: https://chromium.googlesource.com/external/webrtc/+/cbbd8c76e8a8a1cf3f1193ea50980bc9d858458d

TBR=magjed@webrtc.org,tkchin@webrtc.org,denicija@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:7079
Review-Url: https://codereview.webrtc.org/2742603003
Cr-Commit-Position: refs/heads/master@{#17139}
Committed: https://chromium.googlesource.com/external/webrtc/+/a2fb30c8cb29eec755fe931db7bf5aecf0d8dbbf

[kthelgason, 2017-03-09 09:35:04]

Created Reland of Add Metal video view in AppRTCMobile and metal availability
macro.

[kthelgason, 2017-03-09 09:36:53]

Patchset #2 (id:130001) has been deleted

[kthelgason, 2017-03-09 09:38:12]

The CQ bit was checked by kthelgason@webrtc.org to run a CQ dry run

[commit-bot: I haz the power, 2017-03-09 09:38:16]

Dry run: 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, 2017-03-09 09:38:17]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-03-09 09:38:18]

Dry run: This issue passed the CQ dry run.

[kthelgason, 2017-03-09 09:43:27]

Magnus, please take a look when you can.

[kthelgason, 2017-03-09 11:34:14]

The CQ bit was checked by kthelgason@webrtc.org

[commit-bot: I haz the power, 2017-03-09 11:34:22]

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, 2017-03-09 11:34:28]

CQ is committing da patch.

Bot data: {"patchset_id": 150001, "attempt_start_ts": 1489059254131380,
"parent_rev": "e47c1d3ca172e5ea84e59c1e88dbe25664664e54", "commit_rev":
"a2fb30c8cb29eec755fe931db7bf5aecf0d8dbbf"}

[commit-bot: I haz the power, 2017-03-09 11:34:30]

Description was changed from

==========
Reland of Add Metal video view in AppRTCMobile and metal availability macro.
(patchset #1 id:1 of https://codereview.webrtc.org/2739793003/ )

Reason for revert:
Fixing rendering issues in AppRTCMobile

Original issue's description:
> Revert of Add Metal video view in AppRTCMobile and metal availability macro.
(patchset #5 id:80001 of https://codereview.webrtc.org/2722583002/ )
> 
> Reason for revert:
> Breaks AppRTCMobile
> 
> Original issue's description:
> > Add Metal video view in AppRTCMobile and Metal availability macro.
> > 
> > - The RTC_SUPPORTS_METAL macro allows consumers to gracefully handle
compilation for different archs that are not supporting Metal.
> > 
> > BUG=webrtc:7079
> > 
> > Review-Url: https://codereview.webrtc.org/2722583002
> > Cr-Commit-Position: refs/heads/master@{#17004}
> > Committed:
https://chromium.googlesource.com/external/webrtc/+/154a7bb877abefada22afe28b...
> 
> TBR=magjed@webrtc.org,tkchin@webrtc.org,denicija@webrtc.org
> # Not skipping CQ checks because original CL landed more than 1 days ago.
> BUG=webrtc:7079
> 
> Review-Url: https://codereview.webrtc.org/2739793003
> Cr-Commit-Position: refs/heads/master@{#17119}
> Committed:
https://chromium.googlesource.com/external/webrtc/+/cbbd8c76e8a8a1cf3f1193ea5...

TBR=magjed@webrtc.org,tkchin@webrtc.org,denicija@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:7079
==========

to

==========
Reland of Add Metal video view in AppRTCMobile and metal availability macro.
(patchset #1 id:1 of https://codereview.webrtc.org/2739793003/ )

Reason for revert:
Fixing rendering issues in AppRTCMobile

Original issue's description:
> Revert of Add Metal video view in AppRTCMobile and metal availability macro.
(patchset #5 id:80001 of https://codereview.webrtc.org/2722583002/ )
> 
> Reason for revert:
> Breaks AppRTCMobile
> 
> Original issue's description:
> > Add Metal video view in AppRTCMobile and Metal availability macro.
> > 
> > - The RTC_SUPPORTS_METAL macro allows consumers to gracefully handle
compilation for different archs that are not supporting Metal.
> > 
> > BUG=webrtc:7079
> > 
> > Review-Url: https://codereview.webrtc.org/2722583002
> > Cr-Commit-Position: refs/heads/master@{#17004}
> > Committed:
https://chromium.googlesource.com/external/webrtc/+/154a7bb877abefada22afe28b...
> 
> TBR=magjed@webrtc.org,tkchin@webrtc.org,denicija@webrtc.org
> # Not skipping CQ checks because original CL landed more than 1 days ago.
> BUG=webrtc:7079
> 
> Review-Url: https://codereview.webrtc.org/2739793003
> Cr-Commit-Position: refs/heads/master@{#17119}
> Committed:
https://chromium.googlesource.com/external/webrtc/+/cbbd8c76e8a8a1cf3f1193ea5...

TBR=magjed@webrtc.org,tkchin@webrtc.org,denicija@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:7079

Review-Url: https://codereview.webrtc.org/2742603003
Cr-Commit-Position: refs/heads/master@{#17139}
Committed:
https://chromium.googlesource.com/external/webrtc/+/a2fb30c8cb29eec755fe931db...
==========

[commit-bot: I haz the power, 2017-03-09 11:34:31]

Committed patchset #2 (id:150001) as
https://chromium.googlesource.com/external/webrtc/+/a2fb30c8cb29eec755fe931db...

[magjed_webrtc, 2017-03-09 12:37:26]

lgtm