Buffet: Phase 1 of GCD device registration workflow

Implemented the basic device registration workflow in buffet daemon.

Updated buffet_client to perform/test device registration:

Check for device registration:
  buffet_client cr

Getting registered device information:
  buffet_client di

Begin registration (with all default values):
  buffet_client sr

Begin registration with custom parameters:
  buffet_client sr "service_url=http://localhost/buffet&device_kind=coffeePot"

Finalize registration:
  buffet_client fr 4/FsXprlpVsmPw6z7ro7aqU156Eh6V.0ktCYeVc3DwYEnp6UAPFm0GAey3PigI

BUG=chromium:363348
TEST=unit tests passed.

Change-Id: Id8a90b66fbdc366eaa9f62caa82a7cb0abc2e638
Reviewed-on: https://chromium-review.googlesource.com/195082
Tested-by: Alex Vakulenko <avakulenko@chromium.org>
Reviewed-by: Chris Sosa <sosa@chromium.org>
Commit-Queue: Alex Vakulenko <avakulenko@chromium.org>
diff --git a/buffet/buffet.gyp b/buffet/buffet.gyp
index eb140be..12933d4 100644
--- a/buffet/buffet.gyp
+++ b/buffet/buffet.gyp
@@ -32,6 +32,7 @@
         'dbus_constants.cc',
         'dbus_manager.cc',
         'dbus_utils.cc',
+        'device_registration_info.cc',
         'exported_property_set.cc',
         'http_request.cc',
         'http_transport_curl.cc',
@@ -59,6 +60,9 @@
         'buffet_client.cc',
         'dbus_constants.cc',
       ],
+      'dependencies': [
+        'buffet_common',
+      ],
     },
     {
       'target_name': 'buffet_testrunner',