Add iOS SDK unit tests for nalu_rewriter

Bug: webrtc:9939
Change-Id: I6848786009ee10ffed60743d9e3a2acaf65540c6
Reviewed-on: https://webrtc-review.googlesource.com/c/108440
Reviewed-by: Artem Titarenko <artit@webrtc.org>
Reviewed-by: Peter Hanspers <peterhanspers@webrtc.org>
Commit-Queue: Peter Hanspers <peterhanspers@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25422}
diff --git a/sdk/BUILD.gn b/sdk/BUILD.gn
index a8a1b03..ff731ba 100644
--- a/sdk/BUILD.gn
+++ b/sdk/BUILD.gn
@@ -1037,6 +1037,7 @@
             "objc/unittests/RTCPeerConnectionFactory_xctest.m",
             "objc/unittests/frame_buffer_helpers.h",
             "objc/unittests/frame_buffer_helpers.mm",
+            "objc/unittests/nalu_rewriter_xctest.mm",
           ]
 
           # TODO(peterhanspers): Reenable these tests on simulator.
@@ -1059,6 +1060,7 @@
             ":native_api_audio_device_module",
             ":native_video",
             ":peerconnectionfactory_base_objc",
+            ":video_toolbox_cc",
             ":videocapture_objc",
             ":videocodec_objc",
             ":videoframebuffer_objc",
@@ -1599,7 +1601,10 @@
     }
 
     rtc_static_library("video_toolbox_cc") {
-      visibility = [ ":videotoolbox_objc" ]
+      visibility = [
+        ":videotoolbox_objc",
+        ":sdk_unittests_sources",
+      ]
       sources = [
         "objc/components/video_codec/helpers.cc",
         "objc/components/video_codec/helpers.h",