Implement a trivial Mojo EchoService that can be connected to over DBus

mojo/mojo_examples.gypi

Index: mojo/mojo_examples.gypi
diff --git a/mojo/mojo_examples.gypi b/mojo/mojo_examples.gypi
index 4de6fbd755297cc1a48639f99f63c1300415b1f4..5bece9b149c90cfa8fc397c06963f7be24bf0596 100644
--- a/mojo/mojo_examples.gypi
+++ b/mojo/mojo_examples.gypi
@@ -297,5 +297,25 @@
         },
       ],
     }],
+    ['OS=="linux"', {
+      'targets': [
+        {
+          'target_name': 'mojo_dbus_echo',
+          'type': 'shared_library',
+          'dependencies': [
+            '../base/base.gyp:base',
+            'mojo_bindings',
+            'mojo_environment_standalone',
+            'mojo_echo_bindings',
+            'mojo_shell_client',
+            'mojo_system',
+            'mojo_utility',
+          ],
+          'sources': [
+            'examples/dbus_echo/dbus_echo_app.cc',
+          ],
+        },
+      ],
+    }],
   ],
 }