Revert "Ensure method which updates UI is called in main thread"

This reverts commit 0365c99474fd812283842f650cc090b957d73ef2.

Reason for revert: Breaks downstream project.

Original change's description:
> Ensure method which updates UI is called in main thread
>
> Bug: None
> Change-Id: I52d6871e7852e15ef8404377ed37ea894aedae5a
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/216500
> Commit-Queue: Kári Helgason <kthelgason@webrtc.org>
> Reviewed-by: Kári Helgason <kthelgason@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#33881}

TBR=mbonadei@webrtc.org,kthelgason@webrtc.org,kthelgason@google.com,webrtc-scoped@luci-project-accounts.iam.gserviceaccount.com,aidenluo.me@gmail.com

Change-Id: I22e04cefd3766fc9118baaa3bb3464ff03b9bad3
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: None
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/216684
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#33883}
diff --git a/AUTHORS b/AUTHORS
index e314db29..64488bf 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -80,7 +80,6 @@
 Peng Yu <yupeng323@gmail.com>
 Philipp Hancke <philipp.hancke@googlemail.com>
 Piasy Xu <xz4215@gmail.com>
-Qi Luo <aidenluo.me@gmail.com>
 Rafael Lopez Diez <rafalopezdiez@gmail.com>
 Ralph Giles <giles@ghostscript.com>
 Raman Budny <budnyjj@gmail.com>
diff --git a/examples/objc/AppRTCMobile/ARDAppClient.m b/examples/objc/AppRTCMobile/ARDAppClient.m
index 9d5107d..ccd5bb0 100644
--- a/examples/objc/AppRTCMobile/ARDAppClient.m
+++ b/examples/objc/AppRTCMobile/ARDAppClient.m
@@ -212,11 +212,7 @@
     return;
   }
   _state = state;
-  __weak ARDAppClient *weakSelf = self;
-  dispatch_async(dispatch_get_main_queue(), ^{
-    ARDAppClient *strongSelf = weakSelf;
-    [strongSelf.delegate appClient:strongSelf didChangeState:strongSelf.state];
-  });
+  [_delegate appClient:self didChangeState:_state];
 }
 
 - (void)connectToRoomWithId:(NSString *)roomId