buffet: Add DBus proxy class for command instance object

Added DBusCommandProxy class that implements
org.chromium.Buffet.Command DBus interface, including command
methods and properties.

BUG=chromium:374864
TEST=USE=buffet P2_TEST_FILTER="buffet::*" FEATURES=test emerge-link platform2

Change-Id: Iaf17f2b7c276edc1e9f3ca09a759a4a7d4dc3b10
Reviewed-on: https://chromium-review.googlesource.com/213267
Tested-by: Alex Vakulenko <avakulenko@chromium.org>
Reviewed-by: Christopher Wiley <wiley@chromium.org>
diff --git a/buffet/buffet.gyp b/buffet/buffet.gyp
index b95637f..74c1564 100644
--- a/buffet/buffet.gyp
+++ b/buffet/buffet.gyp
@@ -21,6 +21,7 @@
         'commands/command_instance.cc',
         'commands/command_manager.cc',
         'commands/command_queue.cc',
+        'commands/dbus_command_proxy.cc',
         'commands/object_schema.cc',
         'commands/prop_constraints.cc',
         'commands/prop_types.cc',
@@ -68,6 +69,11 @@
           'dependencies': [
             'buffet_common',
           ],
+          'variables': {
+            'deps': [
+              'libchrome-test-<(libbase_ver)',
+            ],
+          },
           'includes': ['../common-mk/common_test.gypi'],
           'sources': [
             'any_unittest.cc',
@@ -78,6 +84,7 @@
             'commands/command_instance_unittest.cc',
             'commands/command_manager_unittest.cc',
             'commands/command_queue_unittest.cc',
+            'commands/dbus_command_proxy_unittest.cc',
             'commands/object_schema_unittest.cc',
             'commands/schema_utils_unittest.cc',
             'commands/unittest_utils.cc',