Add a browsertest for magic iframe.

chrome/chrome_tests.gypi

 # Copyright (c) 2011 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.
 
 {
   'variables' : {
     'pyautolib_sources': [
       'app/chrome_command_ids.h',
       'app/chrome_dll_resource.h',
       'common/automation_constants.h',
@@ skipping 2537 matching lines @@
         'browser/extensions/permissions_apitest.cc',
         'browser/extensions/stubs_apitest.cc',
         'browser/extensions/window_open_apitest.cc',
         'browser/first_run/first_run_browsertest.cc',
         'browser/geolocation/access_token_store_browsertest.cc',
         'browser/geolocation/geolocation_browsertest.cc',
         'browser/gpu_browsertest.cc',
         'browser/history/history_browsertest.cc',
         'browser/idbbindingutilities_browsertest.cc',
         'browser/importer/toolbar_importer_utils_browsertest.cc',
+        'browser/magic_iframe_browsertest.cc',
         'browser/net/cookie_policy_browsertest.cc',
         'browser/net/ftp_browsertest.cc',
         'browser/plugin_data_remover_browsertest.cc',
         'browser/policy/device_management_backend_mock.cc',
         'browser/policy/device_management_backend_mock.h',
         'browser/policy/device_management_service_browsertest.cc',
         'browser/policy/enterprise_metrics_browsertest.cc',
         'browser/policy/enterprise_metrics_enrollment_browsertest.cc',
         'browser/popup_blocker_browsertest.cc',
         'browser/prerender/prerender_browsertest.cc',
@@ skipping 1790 matching lines @@
               # Use outputs of this action as inputs for the main target build.
               # Seems as a misnomer but makes this happy on Linux (scons).
               'process_outputs_as_sources': 1,
             },
           ],  # 'actions'
         },
       ]
     }],  # 'coverage!=0'
   ],  # 'conditions'
 }