Don't show media controls when there is a persistent video.

content/browser/renderer_host/render_view_host_impl.cc

Index: content/browser/renderer_host/render_view_host_impl.cc
diff --git a/content/browser/renderer_host/render_view_host_impl.cc b/content/browser/renderer_host/render_view_host_impl.cc
index e16766aab13439707835941f4cb6061bec504863..8388af1bad8925ce675338110d87c801e8c1f58a 100644
--- a/content/browser/renderer_host/render_view_host_impl.cc
+++ b/content/browser/renderer_host/render_view_host_impl.cc
@@ -532,6 +532,10 @@ WebPreferences RenderViewHostImpl::ComputeWebkitPrefs() {
   if (delegate_ && delegate_->HideDownloadUI())
     prefs.hide_download_ui = true;
 
+  // `media_controls_enabled` is `true` by default.
+  if (delegate_ && delegate_->HasPersistentVideo())
+    prefs.media_controls_enabled = false;
+
   prefs.background_video_track_optimization_enabled =
       base::FeatureList::IsEnabled(media::kBackgroundVideoTrackOptimization);