Disable background video track behind a feature flag

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 e19736a7ecbf312614899a577d0d931039449b59..856e6cb074073504cbc4f1fbf0544ac3443e2a76 100644
--- a/content/browser/renderer_host/render_view_host_impl.cc
+++ b/content/browser/renderer_host/render_view_host_impl.cc
@@ -80,6 +80,7 @@
 #include "content/public/common/result_codes.h"
 #include "content/public/common/url_constants.h"
 #include "content/public/common/url_utils.h"
+#include "media/base/media_switches.h"
 #include "net/base/url_util.h"
 #include "net/url_request/url_request_context_getter.h"
 #include "third_party/skia/include/core/SkBitmap.h"
@@ -526,6 +527,9 @@ WebPreferences RenderViewHostImpl::ComputeWebkitPrefs() {
   if (delegate_ && delegate_->HideDownloadUI())
     prefs.hide_download_ui = true;
 
+  prefs.background_video_track_optimization_enabled =
+      base::FeatureList::IsEnabled(media::kBackgroundVideoTrackOptimization);
+
   std::map<std::string, std::string> expensive_background_throttling_prefs;
   variations::GetVariationParamsByFeature(
       features::kExpensiveBackgroundTimerThrottling,