metrics: Use the new serialization mechanism in libmetrics

Convert libmetrics to the new serialization mechanism living in
//components/metrics in the chrome repo.

BUG=chromium:374368
TEST=FEATURES=test emerge-amd64-generic metrics

Change-Id: Ia8cf128d04fedd9672fb47096dc6fd87d6a9043d
Reviewed-on: https://chromium-review.googlesource.com/207237
Reviewed-by: Luigi Semenzato <semenzato@chromium.org>
Commit-Queue: Bertrand Simonnet <bsimonnet@chromium.org>
Tested-by: Bertrand Simonnet <bsimonnet@chromium.org>
diff --git a/metrics/metrics.gyp b/metrics/metrics.gyp
index 044ff66..7a4338b 100644
--- a/metrics/metrics.gyp
+++ b/metrics/metrics.gyp
@@ -55,7 +55,8 @@
       'target_name': 'libupload_service',
       'type': 'static_library',
       'dependencies': [
-        'metrics_proto'
+        'metrics_proto',
+        '../metrics/libmetrics-<(libbase_ver).gyp:libmetrics-<(libbase_ver)',
       ],
       'link_settings': {
         'libraries': [
@@ -83,8 +84,6 @@
         'uploader/metrics_log.cc',
         'uploader/system_profile_cache.cc',
         'uploader/curl_sender.cc',
-        'components/metrics/chromeos/metric_sample.cc',
-        'components/metrics/chromeos/serialization_utils.cc',
         'components/metrics/metrics_log_base.cc',
         'components/metrics/metrics_log_manager.cc',
         'components/metrics/metrics_hashes.cc',