Prepare for deletion of the NO_MAIN_THREAD_WRAPPING preprocessor define

This is a partial reland of
https://webrtc-review.googlesource.com/c/src/+/39680,
including only the (hopefully) non-problematic parts of it, but
postponing actual deletion of automatic thread wrapping.

Bug: webrtc:9714
Change-Id: I9b79dd073f0e945cbb62f3b54cff05eaaea9b06c
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/141664
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#28265}
diff --git a/sdk/BUILD.gn b/sdk/BUILD.gn
index 60be6db..6036a4d 100644
--- a/sdk/BUILD.gn
+++ b/sdk/BUILD.gn
@@ -1125,6 +1125,7 @@
             ":peerconnectionfactory_base_objc",
             ":sdk_unittests_bundle_data",
             ":sdk_unittests_sources",
+            "../rtc_base",
             "//test:test_support",
           ]
           ldflags = [ "-all_load" ]
@@ -1143,6 +1144,7 @@
           deps = [
             ":framework_objc+link",
             ":ios_framework_bundle",
+            "../rtc_base",
             "//test:test_support",
           ]
         }