Disable background video track behind a feature flag

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index 3c6a78301b1534c766e1303ea6176787e6b28bca..1060d4747c6e3f8bfec92bb006494cefbded0dd4 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -91160,6 +91160,7 @@ value.
   <int value="-2017953534" label="enable-hosted-app-shim-creation"/>
   <int value="-2013551096" label="ViewsSimplifiedFullscreenUI:disabled"/>
   <int value="-2008272679" label="disable-webrtc-hw-encoding"/>
+  <int value="-2005089558" label="BackgroundVideoTrackOptimization:disabled"/>
   <int value="-2003354337"
       label="enable-search-button-in-omnibox-for-str-or-iip"/>
   <int value="-1999892428" label="force-ui-direction"/>
@@ -91571,6 +91572,7 @@ value.
   <int value="-78035185" label="custom_summary"/>
   <int value="-76631048" label="disable-offline-auto-reload-visible-only"/>
   <int value="-70595606" label="ash-enable-unified-desktop"/>
+  <int value="-68877684" label="BackgroundVideoTrackOptimization:enabled"/>
   <int value="-68225452" label="enable-translate-new-ux"/>
   <int value="-58242474" label="ash-disable-swipe-to-close-in-overview-mode"/>
   <int value="-55944747" label="disable-child-account-detection"/>