Make sure RTCMTLVideoView.h ends up in framework headers.

Needs to be added to the array before the array is copied to the
sources and public_headers arrays.

Bug: None
Change-Id: If41fd1c882dd17e4007b62c9c7a49f196849dd12
Reviewed-on: https://webrtc-review.googlesource.com/63640
Reviewed-by: Kári Helgason <kthelgason@webrtc.org>
Commit-Queue: Anders Carlsson <andersc@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22531}
diff --git a/sdk/BUILD.gn b/sdk/BUILD.gn
index e052edf..bd22f42 100644
--- a/sdk/BUILD.gn
+++ b/sdk/BUILD.gn
@@ -859,6 +859,10 @@
             "objc/Framework/Headers/WebRTC/RTCFileLogger.h",
           ]
         }
+        if (rtc_use_metal_rendering) {
+          common_objc_headers +=
+              [ "objc/Framework/Headers/WebRTC/RTCMTLVideoView.h" ]
+        }
 
         sources = common_objc_headers
         public_headers = common_objc_headers
@@ -886,8 +890,6 @@
           "../system_wrappers:runtime_enabled_features_default",
         ]
         if (rtc_use_metal_rendering) {
-          common_objc_headers +=
-              [ "objc/Framework/Headers/WebRTC/RTCMTLVideoView.h" ]
           deps += [ ":metal_objc" ]
         }