Add more components to "gn check"

components/page_load_metrics/browser/BUILD.gn

 # Copyright 2015 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.
 
 # GYP version: components/page_load_metrics.gypi:page_load_metrics_browser
 static_library("browser") {
   sources = [
     "metrics_web_contents_observer.cc",
     "metrics_web_contents_observer.h",
     "page_load_metrics_observer.cc",
     "page_load_metrics_observer.h",
     "page_load_metrics_util.cc",
     "page_load_metrics_util.h",
   ]
   public_deps = [
     "//content/public/browser",
   ]
   deps = [
     "//base",
     "//components/page_load_metrics/common",
+    "//components/rappor",
     "//ipc",
+    "//net",
   ]
 }
 
 source_set("unit_tests") {
   testonly = true
   sources = [
     "metrics_web_contents_observer_unittest.cc",
   ]
   deps = [
     ":browser",
+    "//base",
+    "//base/test:test_support",
+    "//components/page_load_metrics/common",
+    "//components/rappor:test_support",
+    "//content/test:test_support",
+    "//net",
     "//testing/gtest",
   ]
 }