GN rules for everything in //mojo

mojo/examples/png_viewer/BUILD.gn

+# Copyright 2014 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/system.gni")
+
+# GYP version: mojo/mojo_examples.gypi:mojo_png_viewer
+shared_library("png_viewer") {
+  output_name = "mojo_png_viewer"
+
+  sources = [
+    "png_viewer.cc"
+  ]
+
+  deps = [
+    "//mojo/application",
+    "//mojo/examples/media_viewer:bindings",
+    "//mojo/public/cpp/bindings",
+    "//mojo/public/cpp/utility",
+    "//mojo/services/public/cpp/view_manager",
+    "//mojo/services/public/interfaces/content_handler",
+    "//mojo/services/public/interfaces/network",
+    "//skia",
+    "//ui/gfx",
+  ] + mojo_system_for_shared_library
+}