flags: assign load-media-router-component-extension

Bug: None
Change-Id: I9bd5def390e5fbe18d19b42d23540797a7a99d81
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1509353
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Commit-Queue: mark a. foltz <mfoltz@chromium.org>
Auto-Submit: Elly Fong-Jones <ellyjones@chromium.org>
Reviewed-by: mark a. foltz <mfoltz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#638718}

chrome/browser/flag-metadata.json

@@ -2203,8 +2203,12 @@
   },
   {
     "name": "load-media-router-component-extension",
-    // "owners": [ "your-team" ],
-    "expiry_milestone": 76
+    "owners": [ "mfoltz", "media-dev" ],
+    // This flag has two purposes: in-team development/Q&A, and allowing
+    // Chromium users to load this extension, which isn't normally distributed
+    // with Chromium. It can be removed once the extension is removed, which has
+    // external dependencies.
+    "expiry_milestone": -1
   },
   {
     "name": "lsd-permission-prompt",