26afe214ad
Linking external ObjC / Swift apps fails when the app code is using any of the new frame-buffer classes RTCI420Buffer, RTCMutableI420Buffer, or RTCCVPixelBuffer. To fix, we need to add the appropriate attribute to the classes (e.g. using the RTC_EXPORT macro). BUG=None Review-Url: https://codereview.webrtc.org/2961293002 Cr-Commit-Position: refs/heads/master@{#18840}