media/gpu/test: Improve video decoder (performance) tests usage documentation.

This CL updates the documentation for running the video decoder (performance)
tests directly from Tast. Additional info and examples are added to run sets of
tests using wildcards.

TEST=None

BUG=None

Change-Id: I7e05823a8dda2115c7d49c00c5c953bfa21cf739
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1750537
Reviewed-by: Alexandre Courbot <[email protected]>
Commit-Queue: David Staessens <[email protected]>
Cr-Commit-Position: refs/heads/master@{#690659}
diff --git a/docs/media/gpu/video_decoder_test_usage.md b/docs/media/gpu/video_decoder_test_usage.md
index f09c117..e86cc82 100644
--- a/docs/media/gpu/video_decoder_test_usage.md
+++ b/docs/media/gpu/video_decoder_test_usage.md
@@ -15,10 +15,13 @@
 ## Running from Tast
 The Tast framework provides an easy way to run the video decoder tests from a
 ChromeOS chroot. Test data is automatically deployed to the device being tested.
+To run all video decoder tests use:
 
-    tast run <host> video.<test_name>
+    tast run $HOST video.DecodeAccelH264* video.DecodeAccelVP*
 
-e.g.: `tast run $HOST video.DecodeAccelH264`
+Wildcards can be used to run specific sets of tests:
+* Run all VP8 tests: `tast run $HOST video.DecodeAccelVP8*`
+* Run all VP9 profile 2 tests: `tast run $HOST video.DecodeAccelVP92*`
 
 Check the
 [tast video folder](https://chromium.googlesource.com/chromiumos/platform/tast-tests/+/refs/heads/master/src/chromiumos/tast/local/bundles/cros/video/)