Add PrintResults to VideoCodecTest.

These are used by the test runner to pick up perf values
to be shown in the perf dashboard.

Bug: webrtc:10349
Change-Id: Ib3b2479f7a20b66192751bee8237d757f5870bd2
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/126220
Reviewed-by: Mirta Dvornicic <mirtad@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Commit-Queue: Rasmus Brandt <brandtr@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27020}

api/test/videocodec_test_fixture.h

@@ -82,6 +82,9 @@ class VideoCodecTestFixture {
     std::string ToString() const;
     std::string CodecName() const;
 
+    // Name of this config, to be used for accounting by the test runner.
+    std::string test_name;
+
     // Plain name of YUV file to process without file extension.
     std::string filename;