Add metal view, shaders and renderer.

webrtc/sdk/BUILD.gn

Index: webrtc/sdk/BUILD.gn
diff --git a/webrtc/sdk/BUILD.gn b/webrtc/sdk/BUILD.gn
index e610242f6357ff8adaefe51f6c6239c92185cb32..b48c7089f6d53c95b3c278e42fe377b38b7f32ef 100644
--- a/webrtc/sdk/BUILD.gn
+++ b/webrtc/sdk/BUILD.gn
@@ -47,9 +47,14 @@ if (is_ios || is_mac) {
       "objc/Framework/Classes/RTCMetricsSampleInfo.mm",
       "objc/Framework/Classes/RTCSSLAdapter.mm",
       "objc/Framework/Classes/RTCTracing.mm",
+      "objc/Framework/Classes/metal/RTCMTLRenderer.mm",
+      "objc/Framework/Classes/metal/RTCMTLVideoView.m",
+      "objc/Framework/Classes/metal/Shaders.metal",
       "objc/Framework/Headers/WebRTC/RTCDispatcher.h",
       "objc/Framework/Headers/WebRTC/RTCFieldTrials.h",
       "objc/Framework/Headers/WebRTC/RTCLogging.h",
+      "objc/Framework/Headers/WebRTC/RTCMTLRenderer.h",
+      "objc/Framework/Headers/WebRTC/RTCMTLVideoView.h",
       "objc/Framework/Headers/WebRTC/RTCMacros.h",
       "objc/Framework/Headers/WebRTC/RTCMetrics.h",
       "objc/Framework/Headers/WebRTC/RTCMetricsSampleInfo.h",
@@ -67,7 +72,11 @@ if (is_ios || is_mac) {
         "objc/Framework/Headers/WebRTC/RTCCameraPreviewView.h",
         "objc/Framework/Headers/WebRTC/UIDevice+RTCDevice.h",
       ]
-      libs = [ "AVFoundation.framework" ]
+      libs = [
+        "AVFoundation.framework",
+        "Metal.framework",
+        "MetalKit.framework",
+      ]
     }
     if (!build_with_chromium) {
       sources += [