metrics: Import protobufs from Chromium.

Instead of pulling the protobufs from chromium, copy them into
platform2/metrics/proto.
This enables us to add Chromium OS specific changes without polluting
Chromium's protobuf.

BUG=chrome-os-partner:42861
TEST=`FEATURES=test emerge-gizmo metrics` succeeds.

CQ-DEPEND=CL:286895

Change-Id: Ib919a21da6518199c29adb70c8bc27220e0dc031
Reviewed-on: https://chromium-review.googlesource.com/286943
Reviewed-by: Gaurav Shah <gauravsh@chromium.org>
Commit-Queue: Bertrand Simonnet <bsimonnet@chromium.org>
Trybot-Ready: Bertrand Simonnet <bsimonnet@chromium.org>
Tested-by: Bertrand Simonnet <bsimonnet@chromium.org>
diff --git a/metrics/metrics.gyp b/metrics/metrics.gyp
index 3130509..276ec78 100644
--- a/metrics/metrics.gyp
+++ b/metrics/metrics.gyp
@@ -83,17 +83,12 @@
       'target_name': 'metrics_proto',
       'type': 'static_library',
       'variables': {
-        'proto_in_dir': 'components/metrics/proto/',
-        'proto_out_dir': 'include/components/metrics/proto',
+        'proto_in_dir': 'uploader/proto',
+        'proto_out_dir': 'include/metrics/uploader/proto',
       },
       'sources': [
         '<(proto_in_dir)/chrome_user_metrics_extension.proto',
         '<(proto_in_dir)/histogram_event.proto',
-        '<(proto_in_dir)/omnibox_event.proto',
-        '<(proto_in_dir)/omnibox_input_type.proto',
-        '<(proto_in_dir)/perf_data.proto',
-        '<(proto_in_dir)/profiler_event.proto',
-        '<(proto_in_dir)/sampled_profile.proto',
         '<(proto_in_dir)/system_profile.proto',
         '<(proto_in_dir)/user_action_event.proto',
       ],