Migrate component mapping notifier to LUCI-Notify.

This is currently in Gatekeeper. The Gatekeeper version will be removed
once this is live.

Bug: 1094768
Change-Id: I5631c0e2787434c1d4f859ee6095250c92490c38
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2264184
Auto-Submit: Owen Rodley <orodley@chromium.org>
Reviewed-by: Takuto Ikuta <tikuta@chromium.org>
Commit-Queue: Takuto Ikuta <tikuta@chromium.org>
Cr-Commit-Position: refs/heads/master@{#782256}

infra/config/generated/luci-notify.cfg

@@ -781,6 +781,18 @@ notifiers {
     repository: "https://chromium.googlesource.com/chromium/src"
   }
 }
+notifiers {
+  notifications {
+    on_new_status: FAILURE
+    email {
+      recipients: "chromium-component-mapping@google.com"
+    }
+  }
+  builders {
+    bucket: "ci"
+    name: "linux_chromium_component_updater"
+  }
+}
 notifiers {
   notifications {
     on_change: true

infra/config/notifiers.star

@@ -33,3 +33,9 @@ luci.notifier(
         'cronet-bots-observer@google.com',
     ],
 )
+
+luci.notifier(
+    name = 'component-mapping',
+    on_new_status = ['FAILURE'],
+    notify_emails = ['chromium-component-mapping@google.com'],
+)

infra/config/subprojects/chromium/master-only/ci.star

@@ -2824,6 +2824,7 @@ ci.linux_builder(
     schedule = '0 0,6,12,18 * * *',
     service_account = 'component-mapping-updater@chops-service-accounts.iam.gserviceaccount.com',
     triggered_by = [],
+    notifies = ['component-mapping'],
 )