flags: purge metadata of removed flags

This change removes:
  autofill-preview-style
  enable-chromevox-developer-option
  enable-gesture-navigation
  enable-home-launcher
  enable-nup-printing
  enable-policy-tool
  enable-service-worker-servicification
  enable-sync-pseudo-uss-passwords
  offline-bookmarks
  slide-top-chrome-with-page-scrolls
  sync-standalone-transport
from flag-metadata.json.

Bug: None
Change-Id: I93df644583b97c9f8907870d0b35255b2f10a064
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1509335
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Commit-Queue: Avi Drissman <avi@chromium.org>
Auto-Submit: Elly Fong-Jones <ellyjones@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#638717}

chrome/browser/flag-metadata.json

@@ -246,11 +246,6 @@
     // "owners": [ "your-team" ],
     "expiry_milestone": 76
   },
-  {
-    "name": "autofill-preview-style",
-    "owners": [ "ftirelo" ],
-    "expiry_milestone": 73
-  },
   {
     "name": "autofill-profile-client-validation",
     "owners": [ "parastoog" ],
@@ -957,11 +952,6 @@
     "owners": [ "sinhak@chromium.org" ],
     "expiry_milestone": 76
   },
-  {
-    "name": "enable-chromevox-developer-option",
-    // "owners": [ "your-team" ],
-    "expiry_milestone": 76
-  },
   {
     "name": "enable-client-lo-fi",
     "owners": [ "//components/data_reduction_proxy/OWNERS" ],
@@ -1182,11 +1172,6 @@
     "owners": [ "reillyg@chromium.org", "raphael.kubo.da.costa@intel.com" ],
     "expiry_milestone": 76
   },
-  {
-    "name": "enable-gesture-navigation",
-    "owners": [ "jinsukkim@chromium.org" ],
-    "expiry_milestone": 76
-  },
   {
     "name": "enable-google-branded-context-menu",
     "owners": [ "edwardjung@chromium.org" ],
@@ -1226,11 +1211,6 @@
     "owners": [ "shivanisha" ],
     "expiry_milestone": 76
   },
-  {
-    "name": "enable-home-launcher",
-    // "owners": [ "your-team" ],
-    "expiry_milestone": 76
-  },
   {
     "name": "enable-homepage-tile",
     "owners": [ "dimich", "twellington" ],
@@ -1456,11 +1436,6 @@
     "owners": [ "fgorski" ],
     "expiry_milestone": 76
   },
-  {
-    "name": "enable-nup-printing",
-    "owners": [ "skau" ],
-    "expiry_milestone": 76
-  },
   {
     "name": "enable-offer-store-unmasked-wallet-cards",
     // "owners": [ "your-team" ],
@@ -1546,11 +1521,6 @@
     // "owners": [ "your-team" ],
     "expiry_milestone": 76
   },
-  {
-    "name": "enable-policy-tool",
-    // "owners": [ "your-team" ],
-    "expiry_milestone": 76
-  },
   {
     "name": "enable-previews-android-omnibox-ui",
     "owners": [ "//components/data_reduction_proxy/OWNERS" ],
@@ -1642,12 +1612,6 @@
     // "owners": [ "your-team" ],
     "expiry_milestone": 76
   },
-  {
-    "name": "enable-service-worker-servicification",
-    "owners": [ "worker-dev@chromium.org" ],
-    // Enabled by default in M72.
-    "expiry_milestone": 73
-  },
   {
     "name": "enable-shill-sandboxing",
     // "owners": [ "your-team" ],
@@ -1747,11 +1711,6 @@
     "owners": [ "mastiz", "//components/sync/OWNERS" ],
     "expiry_milestone": 76
   },
-  {
-    "name": "enable-sync-pseudo-uss-passwords",
-    "owners": [ "mastiz", "//components/sync/OWNERS" ],
-    "expiry_milestone": 76
-  },
   {
     "name": "enable-sync-pseudo-uss-preferences",
     "owners": [ "mastiz", "//components/sync/OWNERS" ],
@@ -2393,11 +2352,6 @@
     "owners": [ "//device/vr/OWNERS", "xr-dev@chromium.org" ],
     "expiry_milestone": 76
   },
-  {
-    "name": "offline-bookmarks",
-    "owners": [ "jianli", "offline-dev" ],
-    "expiry_milestone": 76
-  },
   {
     "name": "offline-indicator-always-http-probe",
     "owners": [ "jianli", "offline-dev" ],
@@ -2894,11 +2848,6 @@
     // "owners": [ "your-team" ],
     "expiry_milestone": 76
   },
-  {
-    "name": "slide-top-chrome-with-page-scrolls",
-    // "owners": [ "your-team" ],
-    "expiry_milestone": 76
-  },
   {
     "name": "smart-text-selection",
     "owners": [ "djacobo", "linben" ],
@@ -2944,11 +2893,6 @@
     "owners": [ "jkrcal", "//components/sync/OWNERS" ],
     "expiry_milestone": 76
   },
-  {
-    "name": "sync-standalone-transport",
-    "owners": [ "treib", "//components/sync/OWNERS" ],
-    "expiry_milestone": 76
-  },
   {
     "name": "sync-support-secondary-account",
     "owners": [ "treib", "//components/sync/OWNERS" ],