Add unit tests target to GN build.

ui/base/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/ui.gni")
 import("//testing/test.gni")
 
 if (is_android) {
   import("//build/config/android/config.gni")
   import("//build/config/android/rules.gni")
@@ skipping 331 matching lines @@
       "ime/chromeos/ime_keyboard_x11.h",
       "ime/chromeos/ime_keymap.cc",
       "ime/chromeos/ime_keymap.h",
       "ime/chromeos/input_method_delegate.h",
       "ime/chromeos/input_method_descriptor.cc",
       "ime/chromeos/input_method_descriptor.h",
       "ime/chromeos/input_method_manager.cc",
       "ime/chromeos/input_method_manager.h",
       "ime/chromeos/input_method_whitelist.cc",
       "ime/chromeos/input_method_whitelist.h",
+      "ime/chromeos/mock_component_extension_ime_manager_delegate.cc",
+      "ime/chromeos/mock_component_extension_ime_manager_delegate.h",
       "ime/chromeos/mock_ime_candidate_window_handler.cc",
       "ime/chromeos/mock_ime_candidate_window_handler.h",
       "ime/chromeos/mock_ime_engine_handler.cc",
       "ime/chromeos/mock_ime_engine_handler.h",
       "ime/chromeos/mock_ime_input_context_handler.cc",
       "ime/chromeos/mock_ime_input_context_handler.h",
       "ime/composition_text.cc",
       "ime/composition_text.h",
       "ime/composition_text_util_pango.cc",
       "ime/composition_text_util_pango.h",
@@ skipping 558 matching lines @@
       "dragdrop/os_exchange_data_provider_aurax11_unittest.cc",
       "x/selection_requestor_unittest.cc",
     ]
   }
 
   if (is_chromeos) {
     deps += [ "//chromeos" ]
   }
 }
 # TODO(GYP) Mac (ui_base_tests_bundle)