Adds matchers to webrtc::VideoFrame to help with the tests. Bug: webrtc:14003 Change-Id: I62fc1c577bb76b21a96741ba829f6dcd53a308c1 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/260184 Reviewed-by: Rasmus Brandt <brandtr@webrtc.org> Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org> Commit-Queue: Evan Shrubsole <eshr@webrtc.org> Cr-Commit-Position: refs/heads/main@{#36755}