Add owners and extend the expiry milestone for WebRTC ICE related flags.

Bug: None
Change-Id: Idb203866343cefa751a52f25cd1084c0da2f218c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1615714
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#660824}

chrome/browser/flag-metadata.json

@@ -1813,8 +1813,8 @@
   },
   {
     "name": "enable-webrtc-hide-local-ips-with-mdns",
-    // "owners": [ "your-team" ],
-    "expiry_milestone": 76
+    "owners": [ "qingsi", "jeroendb" ],
+    "expiry_milestone": 78
   },
   {
     "name": "enable-webrtc-hw-h264-encoding",
@@ -1858,8 +1858,8 @@
   },
   {
     "name": "enable-webrtc-stun-origin",
-    // "owners": [ "your-team" ],
-    "expiry_milestone": 76
+    "owners": [ "qingsi", "jeroendb" ],
+    "expiry_milestone": 78
   },
   {
     "name": "enable-webvr",