Sync remaining components_unittests with GN

components/power/BUILD.gn

 # 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.
 
 static_library("power") {
   sources = [
     "origin_power_map.cc",
     "origin_power_map.h",
     "origin_power_map_factory.cc",
     "origin_power_map_factory.h",
   ]
 
   deps = [
     "//base",
     "//components/keyed_service/core:core",
     "//content/public/common",
   ]
 }
+
+source_set("unit_tests") {
+  testonly = true
+  sources = [
+    "origin_power_map_unittest.cc",
+  ]
+  deps = [
+    ":power",
+    "//testing/gtest",
+  ]
+}