ARC: Replacing arc/net/OWNERS with WATCHLISTS entries

Unfortunately, non-full committers cannot be owners. Since
this effectively removes all current owners, removing the
OWNERS file so that this directory inherits owners from its
parent. Instead, add the entries in the old OWNERS file to
a watchlist called 'arc_net' so they are notified of
changes.

BUG=None
TEST=python ../depot_tools/watchlists.py \
     components/arc/net/arc_net_host_impl.cc

Review-Url: https://codereview.chromium.org/1946943002
Cr-Commit-Position: refs/heads/master@{#391679}

WATCHLISTS

@@ -75,6 +75,12 @@
     'apps': {
       'filepath': '^apps/',
     },
+    'arc': {
+      'filepath': 'arc/',
+    },
+    'arc_net': {
+      'filepath': 'components/arc/net/',
+    },
     'ash': {
       'filepath': 'ash/',
     },
@@ -1312,6 +1318,12 @@
     'app_shortcuts': ['mgiuca@chromium.org', 'tapted@chromium.org'],
     'appcache': ['michaeln@chromium.org'],
     'apps': ['tfarina@chromium.org', 'chromium-apps-reviews@chromium.org'],
+    'arc': ['elijahtaylor+arcwatch@chromium.org',
+            'lhchavez+watch@chromium.org',
+            'yusukes+watch@chromium.org'],
+    'arc_net': ['abhishekbh@chromium.org',
+                'cernekee@chromium.org',
+                'snanda@chromium.org'],
     'ash': ['sadrul@chromium.org',
             'kalyan.kondapally@intel.com'],
     'aura': ['sadrul@chromium.org',