Make chrome/common compile in GN

components/metrics/proto/BUILD.gn

Index: components/metrics/proto/BUILD.gn
diff --git a/components/metrics/proto/BUILD.gn b/components/metrics/proto/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..2b3c83081fc9b851a459c52b1ad0b7393893d43d
--- /dev/null
+++ b/components/metrics/proto/BUILD.gn
@@ -0,0 +1,20 @@
+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//third_party/protobuf/proto_library.gni")
+
+# GYP version: components/
+proto_library("proto") {
+  sources = [
+    "chrome_user_metrics_extension.proto",
+    "histogram_event.proto",
+    "omnibox_event.proto",
+    "omnibox_input_type.proto",
+    "perf_data.proto",
+    "profiler_event.proto",
+    "sampled_profile.proto",
+    "system_profile.proto",
+    "user_action_event.proto",
+  ]
+}