Remove autoplay-muted-videos 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 06b87dee74126c7fda96f44a6a9c56acb4be6d70..8887e8c5bf09c2b69a223f046c30293b5ecac531 100644
--- a/chrome/app/generated_resources.grd
+++ b/chrome/app/generated_resources.grd
@@ -5872,12 +5872,6 @@ Keep your key file in a safe place. You will need it to create new versions of y
           <message name="IDS_FLAGS_IMPORTANT_SITES_IN_CBD_DESCRIPTION" desc="Description for the flag for using important sites whitelisting in the clear browsing dialog.">
               Include the option to whitelist important sites in the clear browsing data dialog.
           </message>
-          <message name="IDS_FLAGS_ENABLE_AUTOPLAY_MUTED_VIDEOS_NAME" desc="Title for the flag to enable autoplay of muted videos.">
-              Autoplay muted videos
-          </message>
-          <message name="IDS_FLAGS_ENABLE_AUTOPLAY_MUTED_VIDEOS_DESCRIPTION" desc="Description for the flag to enable autoplay of muted videos.">
-              Allow muted videos to autoplay.
-          </message>
       </if>
       <if expr="use_ash">
         <message name="IDS_FLAGS_ASH_MD" desc="Title of the flag which enables or disables material design in Chrome OS system UI.">