Reland of Decoupling rtc_base from Obj-C code

Reland of Decoupling rtc_base from Obj-C code (patchset #1 id:1 of https://codereview.webrtc.org/3008103002/ )

Reason for revert:
Trying to reland after fixing downstream project.

Original issue's description:
> Revert of Decoupling rtc_base from Obj-C code (patchset #8 id:140001 of https://codereview.webrtc.org/3001623003/ )
> 
> Reason for revert:
> It breaks a downstream project.
> 
> Original issue's description:
> > Decoupling rtc_base from Obj-C code
> > 
> > The goal of this CL is to separate Obj-C/Obj-C++ code from targets which have
> > also C++ code (see https://bugs.chromium.org/p/webrtc/issues/detail?id=7743
> > for more information).
> > 
> > To achieve this we have created 2 targets (rtc_base_objc and rtc_base_generic)
> > and rtc_base will act as a proxy between these targets (this way we can avoid a
> > circular dependency between rtc_base_generic and rtc_base_objc).
> > 
> > BUG=webrtc:7743
> > 
> > Review-Url: https://codereview.webrtc.org/3001623003
> > Cr-Commit-Position: refs/heads/master@{#19661}
> > Committed: https://chromium.googlesource.com/external/webrtc/+/a0a5b98937de0f0bf90e17011d2cbc8c632cb409
> 
> TBR=kjellander@webrtc.org,kwiberg@webrtc.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=webrtc:7743
> 
> Review-Url: https://codereview.webrtc.org/3008103002
> Cr-Commit-Position: refs/heads/master@{#19664}
> Committed: https://chromium.googlesource.com/external/webrtc/+/791a8f611da8cc6b0668ccc03bf7525e6ba72a46

TBR=kjellander@webrtc.org,kwiberg@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:7743
Review-Url: https://codereview.webrtc.org/3004373002
Cr-Commit-Position: refs/heads/master@{#19681}
Committed: https://chromium.googlesource.com/external/webrtc/+/a0c893f324da5c9f0773f8990a29cd24643864e4

[mbonadei, 2017-09-04 20:55:22]

Created Reland of Decoupling rtc_base from Obj-C code

[kwiberg-webrtc, 2017-09-04 23:20:52]

Relanding without any changes at all? lgtm

[kjellander_webrtc, 2017-09-05 04:52:03]

On 2017/09/04 23:20:52, kwiberg-webrtc wrote:
> Relanding without any changes at all? lgtm

Right, no need to wait for approval in such cases. lgtm

[mbonadei, 2017-09-05 09:59:17]

The CQ bit was checked by mbonadei@webrtc.org

[commit-bot: I haz the power, 2017-09-05 09:59:22]

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, 2017-09-05 09:59:26]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1504605557559020, "parent_rev":
"fb4e677da0aa57ed638ce4146915e9ce0d443995", "commit_rev":
"a0c893f324da5c9f0773f8990a29cd24643864e4"}

[commit-bot: I haz the power, 2017-09-05 09:59:33]

Description was changed from

==========
Reland of Decoupling rtc_base from Obj-C code (patchset #1 id:1 of
https://codereview.webrtc.org/3008103002/ )

Reason for revert:
Trying to reland after fixing downstream project.

Original issue's description:
> Revert of Decoupling rtc_base from Obj-C code (patchset #8 id:140001 of
https://codereview.webrtc.org/3001623003/ )
> 
> Reason for revert:
> It breaks a downstream project.
> 
> Original issue's description:
> > Decoupling rtc_base from Obj-C code
> > 
> > The goal of this CL is to separate Obj-C/Obj-C++ code from targets which
have
> > also C++ code (see https://bugs.chromium.org/p/webrtc/issues/detail?id=7743
> > for more information).
> > 
> > To achieve this we have created 2 targets (rtc_base_objc and
rtc_base_generic)
> > and rtc_base will act as a proxy between these targets (this way we can
avoid a
> > circular dependency between rtc_base_generic and rtc_base_objc).
> > 
> > BUG=webrtc:7743
> > 
> > Review-Url: https://codereview.webrtc.org/3001623003
> > Cr-Commit-Position: refs/heads/master@{#19661}
> > Committed:
https://chromium.googlesource.com/external/webrtc/+/a0a5b98937de0f0bf90e17011...
> 
> TBR=kjellander@webrtc.org,kwiberg@webrtc.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=webrtc:7743
> 
> Review-Url: https://codereview.webrtc.org/3008103002
> Cr-Commit-Position: refs/heads/master@{#19664}
> Committed:
https://chromium.googlesource.com/external/webrtc/+/791a8f611da8cc6b0668ccc03...

TBR=kjellander@webrtc.org,kwiberg@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:7743
==========

to

==========
Reland of Decoupling rtc_base from Obj-C code (patchset #1 id:1 of
https://codereview.webrtc.org/3008103002/ )

Reason for revert:
Trying to reland after fixing downstream project.

Original issue's description:
> Revert of Decoupling rtc_base from Obj-C code (patchset #8 id:140001 of
https://codereview.webrtc.org/3001623003/ )
> 
> Reason for revert:
> It breaks a downstream project.
> 
> Original issue's description:
> > Decoupling rtc_base from Obj-C code
> > 
> > The goal of this CL is to separate Obj-C/Obj-C++ code from targets which
have
> > also C++ code (see https://bugs.chromium.org/p/webrtc/issues/detail?id=7743
> > for more information).
> > 
> > To achieve this we have created 2 targets (rtc_base_objc and
rtc_base_generic)
> > and rtc_base will act as a proxy between these targets (this way we can
avoid a
> > circular dependency between rtc_base_generic and rtc_base_objc).
> > 
> > BUG=webrtc:7743
> > 
> > Review-Url: https://codereview.webrtc.org/3001623003
> > Cr-Commit-Position: refs/heads/master@{#19661}
> > Committed:
https://chromium.googlesource.com/external/webrtc/+/a0a5b98937de0f0bf90e17011...
> 
> TBR=kjellander@webrtc.org,kwiberg@webrtc.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=webrtc:7743
> 
> Review-Url: https://codereview.webrtc.org/3008103002
> Cr-Commit-Position: refs/heads/master@{#19664}
> Committed:
https://chromium.googlesource.com/external/webrtc/+/791a8f611da8cc6b0668ccc03...

TBR=kjellander@webrtc.org,kwiberg@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:7743

Review-Url: https://codereview.webrtc.org/3004373002
Cr-Commit-Position: refs/heads/master@{#19681}
Committed:
https://chromium.googlesource.com/external/webrtc/+/a0c893f324da5c9f0773f8990...
==========

[commit-bot: I haz the power, 2017-09-05 09:59:34]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/external/webrtc/+/a0c893f324da5c9f0773f8990...

[mbonadei, 2017-09-05 12:16:55]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.webrtc.org/3007183002/ by mbonadei@webrtc.org.

The reason for reverting is: It breaks a chromium FYI trybot (the switch from
rtc_static_library to rtc_source_set seems to be the problem)..