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

content/public/common/web_preferences.h

Index: content/public/common/web_preferences.h
diff --git a/content/public/common/web_preferences.h b/content/public/common/web_preferences.h
index ccabaecf05836385c05fcb5108eaa673ba9a3158..71ea3098a414a9f5f2010f2d33ae64a445f857fd 100644
--- a/content/public/common/web_preferences.h
+++ b/content/public/common/web_preferences.h
@@ -284,6 +284,9 @@ struct CONTENT_EXPORT WebPreferences {
   // Whether it is a presentation receiver.
   bool presentation_receiver;
 
+  // If disabled, media controls should never be used.
+  bool media_controls_enabled;
+
   // We try to keep the default values the same as the default values in
   // chrome, except for the cases where it would require lots of extra work for
   // the embedder to use the same default value.