Cleanup of component/metrics for GN.

components/metrics/BUILD.gn

Index: components/metrics/BUILD.gn
diff --git a/components/metrics/BUILD.gn b/components/metrics/BUILD.gn
index 617c691bdc43762d4227fa76e23e559d965a0a2b..8bccd4582ab779b9f312198c973cd66462e51bba 100644
--- a/components/metrics/BUILD.gn
+++ b/components/metrics/BUILD.gn
@@ -52,6 +52,10 @@ source_set("metrics") {
     "//components/variations",
     "//third_party/zlib",
   ]
+
+  if (is_chromeos) {
+    deps += [ ":serialization" ]
+  }
 }
 
 # GYP version: components/metrics.gypi:metrics_gpu
@@ -121,4 +125,17 @@ static_library("test_support") {
   ]
 }
 
+if (is_linux) {
+  # GYP version: components/metrics.gypi:metrics_serialization
+  source_set("serialization") {
+    sources = [
+      "serialization/serialization_utils.cc",
+      "serialization/serialization_utils.h",
+      "serialization/metric_sample.cc",
+      "serialization/metric_sample.h",
+    ]
+    deps = [ "//base" ]
+  }
+}
+
 # TODO(GYP): metrics_chromeos