Marina Ciocea 1148fd5cef Define MockFrameTransformer in test/.
Add MockFrameTransformer to test/, and remove definitions from unit test
files.

Bug: webrtc:11380
Change-Id: Ia709883e8d000852e3f71e7bfb87877072e22aeb
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/174001
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Commit-Queue: Marina Ciocea <marinaciocea@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31151}
2020-05-04 13:45:22 +00:00
..
2020-02-27 14:27:23 +00:00