flags: assign two tracing flags

This change assigns:
  enable-navigation-tracing
  trace-upload-url
to tracing@ and marks them to expire in M80.

Bug: None
Change-Id: Ie28496728d26409ca979a08d2a33db9999c143c9
Reviewed-on: https://chromium-review.googlesource.com/c/1475808
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Commit-Queue: oysteine <oysteine@chromium.org>
Auto-Submit: Elly Fong-Jones <ellyjones@chromium.org>
Reviewed-by: oysteine <oysteine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#632733}

chrome/browser/flag-metadata.json

@@ -1424,8 +1424,8 @@
   },
   {
     "name": "enable-navigation-tracing",
-    // "owners": [ "your-team" ],
-    "expiry_milestone": 76
+    "owners": [ "tracing" ],
+    "expiry_milestone": 80
   },
   {
     "name": "enable-network-logging-to-file",
@@ -3006,8 +3006,8 @@
   },
   {
     "name": "trace-upload-url",
-    // "owners": [ "your-team" ],
-    "expiry_milestone": 76
+    "owners": [ "tracing" ],
+    "expiry_milestone": 80
   },
   {
     "name": "translate-android-manual-trigger",