Disable background video track behind a feature flag

chrome/app/generated_resources.grd

Index: chrome/app/generated_resources.grd
diff --git a/chrome/app/generated_resources.grd b/chrome/app/generated_resources.grd
index 0d8ad55d84a8b2e6ff7ff8ed7264b1b9901ba7cc..714b7c71867509513eb5281590ada46a036a26dc 100644
--- a/chrome/app/generated_resources.grd
+++ b/chrome/app/generated_resources.grd
@@ -15579,6 +15579,14 @@ read aloud to screenreader users to announce that a completion is available.">
       Use the new audio rendering mixing strategy.
     </message>
 
+    <!-- Background video track disabling experiment strings. -->
+    <message name="IDS_BACKGROUND_VIDEO_TRACK_OPTIMIZATION_NAME" desc="Name of the flag for enabling optimizing background video playback.">
+      Optimize background video playback.
+    </message>
+    <message name="IDS_BACKGROUND_VIDEO_TRACK_OPTIMIZATION_DESCRIPTION" desc="Description of the flag for enabling optimizing background video playback.">
+      Disable video tracks when the video is played in the background to optimize performance.
+    </message>
+
     <if expr="is_win">
       <message name="IDS_UTILITY_PROCESS_SHELL_HANDLER_NAME" desc="The name of the utility process used to handle shell operations.">
         Shell Handler