Add an XPC service to handle alert notifications on mac

chrome/browser/ui/cocoa/notifications/BUILD.gn

 # Copyright 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import("//build/util/branding.gni")
+import("//build/config/mac/rules.gni")
+
+mac_app_bundle("alert_notification_xpc_service") {
+  output_name = "AlertNotificationService"
+  package_type = "xpc"
+
+  info_plist = "xpc-Info.plist"
+  extra_substitutions = [ "CHROME_BUNDLE_ID=$chrome_mac_bundle_id" ]
+
+  sources = [
+    "alert_notification_service.h",
+    "alert_notification_service.mm",
+    "notification_service_delegate.h",
+    "notification_service_delegate.mm",
+    "xpc_service_main.mm",
+  ]
+
+  deps = [
+    ":common",
+    "//base:base",
+  ]
+
+  libs = [
+    "AppKit.framework",
+    "Foundation.framework",
+  ]
+
+  ldflags = []
+  if (is_component_build) {
+    ldflags += [
+      # The XPC service is in Chromium.app/Contents/Versions/X/Chromium \
+      # Framework.framework/XPCServices/AlertNotificationService.xpc/\
+      # Contents/MacOS/ so set rpath up to the base.
+      "-rpath",
+      "@loader_path/../../../../../../../../../",
+    ]
+  }
+}
+
 static_library("common") {
   sources = [
     "notification_builder_mac.h",
     "notification_builder_mac.mm",
     "notification_constants_mac.h",
     "notification_constants_mac.mm",
     "notification_delivery.h",
     "notification_response_builder_mac.h",
     "notification_response_builder_mac.mm",
   ]
 
   deps = [
-    "//base",
+    "//base:base",
   ]
 }