Add some .h files under chrome/browser to .gn files.

chrome/test/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.
 
 import("//build/config/chrome_build.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//chrome/common/features.gni")
@@ skipping 602 matching lines @@
         "../browser/chromeos/login/login_ui_browsertest.cc",
         "../browser/chromeos/login/mixin_based_browser_test.cc",
         "../browser/chromeos/login/mixin_based_browser_test.h",
         "../browser/chromeos/login/oobe_browsertest.cc",
         "../browser/chromeos/login/screenshot_testing/SkDiffPixelsMetric.h",
         "../browser/chromeos/login/screenshot_testing/SkDiffPixelsMetric_cpu.cpp",
         "../browser/chromeos/login/screenshot_testing/SkImageDiffer.cpp",
         "../browser/chromeos/login/screenshot_testing/SkImageDiffer.h",
         "../browser/chromeos/login/screenshot_testing/SkPMetric.cpp",
         "../browser/chromeos/login/screenshot_testing/SkPMetric.h",
+        "../browser/chromeos/login/screenshot_testing/SkPMetricUtil_gen.h",
+        "../browser/chromeos/login/screenshot_testing/login_screen_areas.h",
         "../browser/chromeos/login/screenshot_testing/screenshot_tester.cc",
         "../browser/chromeos/login/screenshot_testing/screenshot_tester.h",
         "../browser/chromeos/login/screenshot_testing/screenshot_testing_mixin.cc",
         "../browser/chromeos/login/screenshot_testing/screenshot_testing_mixin.h",
         "../browser/chromeos/login/test/https_forwarder.cc",
         "../browser/chromeos/login/test/https_forwarder.h",
         "../browser/chromeos/login/test/oobe_base_test.cc",
         "../browser/chromeos/login/test/oobe_base_test.h",
         "../browser/chromeos/login/users/wallpaper/wallpaper_manager_browsertest.cc",
         "../browser/chromeos/login/users/wallpaper/wallpaper_manager_test_utils.cc",
@@ skipping 4586 matching lines @@
 }
 
 if (is_win) {
   loadable_module("conflicts_dll") {
     testonly = true
     sources = [
       "conflicts/conflicts_dll.cc",
     ]
   }
 }