Revert "metrics: Fix the import path of protobufs."

This reverts commit 54297164b4258cd8098903a38fb3837c462e2db1.

Dependent CL reverted.

Change-Id: I35b4ede8b2f67d9dade60869cfbddea81ebeb556
Reviewed-on: https://chromium-review.googlesource.com/264784
Tested-by: Bertrand Simonnet <bsimonnet@chromium.org>
Reviewed-by: Bertrand Simonnet <bsimonnet@chromium.org>
diff --git a/metrics/metrics.gyp b/metrics/metrics.gyp
index 7134e55..3130509 100644
--- a/metrics/metrics.gyp
+++ b/metrics/metrics.gyp
@@ -83,7 +83,7 @@
       'target_name': 'metrics_proto',
       'type': 'static_library',
       'variables': {
-        'proto_in_dir': '../../components/metrics/proto/',
+        'proto_in_dir': 'components/metrics/proto/',
         'proto_out_dir': 'include/components/metrics/proto',
       },
       'sources': [