[RemotePlayback] Don't expose Remote Playback API for WebView.

content/child/runtime_features.cc

Index: content/child/runtime_features.cc
diff --git a/content/child/runtime_features.cc b/content/child/runtime_features.cc
index 34ce8017167787b100634251c99172dbe2b9cb07..bc4784dfd297fa3b61302a189fbff7e577f31b39 100644
--- a/content/child/runtime_features.cc
+++ b/content/child/runtime_features.cc
@@ -202,6 +202,9 @@ void SetRuntimeFeaturesDefaultsAndUpdateFromArgs(
   if (command_line.HasSwitch(switches::kDisablePresentationAPI))
     WebRuntimeFeatures::enablePresentationAPI(false);
 
+  if (command_line.HasSwitch(switches::kDisableRemotePlaybackAPI))
+    WebRuntimeFeatures::enableRemotePlaybackAPI(false);
+
   const std::string webfonts_intervention_v2_group_name =
       base::FieldTrialList::FindFullName("WebFontsInterventionV2");
   const std::string webfonts_intervention_v2_about_flag =