Resurrect the cloud printer driver.

cloud_print/virtual_driver/win/port_monitor/BUILD.gn

Index: cloud_print/virtual_driver/win/port_monitor/BUILD.gn
diff --git a/cloud_print/virtual_driver/win/port_monitor/BUILD.gn b/cloud_print/virtual_driver/win/port_monitor/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..c89863476ff3b9e30e3afc020832f17f6e2c330b
--- /dev/null
+++ b/cloud_print/virtual_driver/win/port_monitor/BUILD.gn
@@ -0,0 +1,59 @@
+# Copyright 2015 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("//chrome/process_version_rc_template.gni")
+
+assert(is_win)
+
+group("port_monitor") {
+  public_deps = [
+    ":port_monitor_dll",
+  ]
+}
+
+shared_library("port_monitor_dll") {
+  output_name = "gcp_portmon"
+
+  sources = [
+    "port_monitor.def",
+    "port_monitor_dll.cc",
+  ]
+
+  deps = [
+    ":lib",
+    ":resources",
+    "//base",
+    "//chrome/common:constants",
+    "//chrome/common:version_header",
+    "//cloud_print/common",
+    "//cloud_print/virtual_driver/win",
+  ]
+
+  libs = [ "userenv.lib" ]
+}
+
+source_set("lib") {
+  sources = [
+    "port_monitor.cc",
+    "port_monitor.h",
+  ]
+
+  deps = [
+    "//base",
+    "//chrome/common:constants",
+    "//chrome/installer/launcher_support",
+    "//cloud_print/common",
+    "//cloud_print/virtual_driver/win",
+  ]
+}
+
+process_version_rc_template("resources") {
+  sources = [
+    "../gcp_portmon_dll.ver",
+  ]
+
+  # Note: target_gen_dir will be different for each toolchain so the output
+  # name doesn't need mangling.
+  output = "$target_gen_dir/gcp_portmon_dll.rc"
+}