Convert printing IPCs to Mojo

components/printing/common/BUILD.gn

 # 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("//mojo/public/tools/bindings/mojom.gni")
+
 static_library("common") {
   sources = [
     "print_messages.cc",
     "print_messages.h",
+    "printing_param_traits.cc",
+    "printing_param_traits.h",
     "printing_param_traits_macros.h",
   ]
 
   deps = [
     "//base",
     "//ipc",
     "//printing",
     "//third_party/WebKit/public:blink_headers",
     "//ui/gfx",
     "//ui/gfx/geometry",
     "//ui/gfx/ipc",
     "//ui/gfx/ipc/geometry",
     "//ui/gfx/ipc/skia",
   ]
 }
+
+mojom("interfaces") {
+  sources = [
+    "printing.mojom",
+  ]
+
+  public_deps = [
+    "//mojo/common:common_custom_types",
+  ]
+}