Reland of Add unit tests for RTCMTLVideoView.

webrtc/sdk/BUILD.gn

Index: webrtc/sdk/BUILD.gn
diff --git a/webrtc/sdk/BUILD.gn b/webrtc/sdk/BUILD.gn
index 4acf3783f545259ac77f82027932f9ba2a03628d..a789efb57e4c668a7b12b3f9e5539c067e519d9a 100644
--- a/webrtc/sdk/BUILD.gn
+++ b/webrtc/sdk/BUILD.gn
@@ -94,6 +94,7 @@
 
   rtc_static_library("rtc_sdk_peerconnection_objc") {
     sources = [
+      "objc/Framework/Classes/Metal/RTCMTLNV12Renderer.h",
       "objc/Framework/Classes/RTCAVFoundationVideoCapturerInternal.h",
       "objc/Framework/Classes/RTCAVFoundationVideoCapturerInternal.mm",
       "objc/Framework/Classes/RTCAVFoundationVideoSource+Private.h",
@@ -257,6 +258,12 @@
         "objc/Framework/UnitTests/RTCSessionDescriptionTest.mm",
         "objc/Framework/UnitTests/avformatmappertests.mm",
       ]
+      if (is_ios) {
+        sources += [ "objc/Framework/UnitTests/RTCMTLVideoViewTests.mm" ]
+        if (current_cpu != "arm64") {
+          sources += [ "objc/Framework/Classes/Metal/RTCMTLVideoView.m" ]
+        }
+      }
       deps = [
         ":rtc_sdk_peerconnection_objc",
         "//third_party/ocmock",