Add end-to-end test for ColorSpace information

Bug: webrtc:8651
Change-Id: Ib7f6162c8dd41868b7d7acca8a6292b2d911c520
Reviewed-on: https://webrtc-review.googlesource.com/c/113941
Commit-Queue: Johannes Kron <kron@webrtc.org>
Reviewed-by: Niels Moller <nisse@webrtc.org>
Reviewed-by: Sebastian Jansson <srte@webrtc.org>
Reviewed-by: Erik Språng <sprang@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25992}
diff --git a/test/frame_generator.h b/test/frame_generator.h
index a92c3b4..45cc9f0 100644
--- a/test/frame_generator.h
+++ b/test/frame_generator.h
@@ -50,6 +50,9 @@
   virtual ~FrameGenerator() = default;
 
   // Returns video frame that remains valid until next call.
+  // TODO(kron): Return rtc::scoped_refptr<VideoFrameBuffer> instead of
+  // VideoFrame* and populate the VideoFrame struct in FrameGeneratorCapturer
+  // using VideoFrame::Builder.
   virtual VideoFrame* NextFrame() = 0;
 
   // Change the capture resolution.