This CL handles frame rotation by updating the OpenGL vertex data in RTCOpenGLVideoRenderer, instead of calling the expensive libyuv::I420Rotate that will rotate the actual memory. Also, we can handle rotated native frames instead of falling back to NativeToI420Buffer. Review-Url: https://codereview.webrtc.org/2176623002 Cr-Commit-Position: refs/heads/master@{#13715}