[DevTools] Move DevToolsWindow testing code to a separate class.

chrome/chrome_tests.gypi

 # Copyright 2013 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.
 {
   'includes': [
     'js_unittest_vars.gypi',
   ],
   'targets': [
     {
       'target_name': 'interactive_ui_tests',
@@ skipping 1022 matching lines @@
         'browser/chromeos/ui/idle_logout_dialog_view_browsertest.cc',
         'browser/collected_cookies_browsertest.cc',
         'browser/content_settings/content_settings_browsertest.cc',
         'browser/crash_recovery_browsertest.cc',
         'browser/custom_handlers/protocol_handler_registry_browsertest.cc',
         'browser/devtools/device/adb/adb_client_socket_browsertest.cc',
         'browser/devtools/device/adb/mock_adb_server.cc',
         'browser/devtools/device/adb/mock_adb_server.h',
         'browser/devtools/device/port_forwarding_browsertest.cc',
         'browser/devtools/device/usb/android_usb_browsertest.cc',
+        'browser/devtools/devtools_window_testing.h',
+        'browser/devtools/devtools_window_testing.cc',
         'browser/devtools/devtools_sanity_browsertest.cc',
         'browser/dom_distiller/dom_distiller_viewer_source_browsertest.cc',
         'browser/dom_distiller/tab_utils_browsertest.cc',
         'browser/do_not_track_browsertest.cc',
         'browser/download/download_browsertest.cc',
         'browser/download/download_browsertest.h',
         'browser/download/download_danger_prompt_browsertest.cc',
         'browser/download/download_started_animation_browsertest.cc',
         'browser/download/save_page_browsertest.cc',
         'browser/errorpage_browsertest.cc',
@@ skipping 1948 matching lines @@
             ['enable_webrtc==1', {
               'dependencies': [
                 '../third_party/libjingle/libjingle.gyp:libjingle_webrtc'
               ]
             }],
           ],
         }]
     }],
   ],  # 'conditions'
 }