Use VideoSourceInterface for owning test video sources

CallTest, VideoQualityTest and VideoAnalyzer used test::TestVideoCapturer
as an interface for video sources. Change to use VideoSourceInterface instead,
since that's all they need.

This is a preparation for making test::VcmCapturer usable as a
VideoTrackSource, and replace use of cricket::VideoCapturer in example code.

Bug: webrtc:6353
Change-Id: I445f5f6f9b7342230b89f53a5722df9c9e92834f
Reviewed-on: https://webrtc-review.googlesource.com/c/114881
Commit-Queue: 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@{#26047}
diff --git a/video/BUILD.gn b/video/BUILD.gn
index 5df2c02..a1d17fd 100644
--- a/video/BUILD.gn
+++ b/video/BUILD.gn
@@ -240,8 +240,10 @@
       "../api:video_quality_test_fixture_api",
       "../api/video:builtin_video_bitrate_allocator_factory",
       "../api/video:video_bitrate_allocator_factory",
+      "../api/video:video_frame",
       "../call:fake_network",
       "../call:simulated_network",
+      "../common_video",
       "../logging:rtc_event_log_api",
       "../logging:rtc_event_log_impl_output",
       "../media:rtc_audio_video",