[webrtc-stats] Only expose hardware capabilities when capturing media

With a recent change to the webrtc-stats spec, user agents with a
fullscreen element will no longer have access to stats which expose
hardware capabilities.

The WPT tests for hardware capability stats has been updated to reflect
the fact that having a fullscreen element is not sufficient anymore,
rather than just removing these tests. This helps catch user agents that
have not updated to reflect this change to the spec.

Bug: 1398362
Change-Id: I221be5bfb900952c29459ce38b1fa1460205a1e3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4084785
Auto-Submit: Evan Shrubsole <[email protected]>
Commit-Queue: Harald Alvestrand <[email protected]>
Reviewed-by: Harald Alvestrand <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1080815}

webrtc-stats/hardware-capability-stats.https.html

@@ -76,8 +76,10 @@
     const stream = await getNoiseStream({video: true, audio: true});
     const statsEntry = await setupPcAndGetStatEntry(t, stream, type, kind, stat);
     assert_not_own_property(statsEntry, stat);
-  }, stat + " not exposed when not capturing or fullscreen.");
+  }, stat + " not exposed when not capturing.");
 
+  // Exposing hardware capabilities when a there is a fullscreen element was
+  // removed with https://github.com/w3c/webrtc-stats/pull/713.
   promise_test(async (t) => {
     const stream = await getNoiseStream({video: true, audio: true});
 
@@ -87,8 +89,8 @@
 
     const statsEntry = await setupPcAndGetStatEntry(
       t, stream, type, kind, stat);
-    assert_own_property(statsEntry, stat);
-  }, stat + " exposed when fullscreen.");
+    assert_not_own_property(statsEntry, stat);
+  }, stat + " not exposed when fullscreen and not capturing.");
 
   promise_test(async (t) => {
     const stream = await navigator.mediaDevices.getUserMedia(