Add PDF compositor service

components/printing/service/public/cpp/BUILD.gn

Index: components/printing/service/public/cpp/BUILD.gn
diff --git a/components/printing/service/public/cpp/BUILD.gn b/components/printing/service/public/cpp/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..61c7a358ec81fd64c9e0b09ae499073513393c93
--- /dev/null
+++ b/components/printing/service/public/cpp/BUILD.gn
@@ -0,0 +1,17 @@
+# Copyright 2017 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")
+
+source_set("cpp") {
+  sources = [
+    "pdf_compositor_client.cc",
+    "pdf_compositor_client.h",
+  ]
+
+  public_deps = [
+    "//components/printing/service/public/interfaces",
+    "//services/service_manager/public/cpp",
+  ]
+}