Fix race conditions in ImageDecoder.

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.
 {
   'variables': {
     'chrome_browser_extensions_test_support_sources': [
       # A list of sources which is shared between different browser tests.
       'browser/apps/app_browsertest_util.cc',
       'browser/apps/app_browsertest_util.h',
       'browser/extensions/browsertest_util.cc',
@@ skipping 274 matching lines @@
       'browser/external_extension_browsertest.cc',
       'browser/fast_shutdown_browsertest.cc',
       'browser/favicon/content_favicon_driver_browsertest.cc',
       'browser/first_run/first_run_browsertest.cc',
       'browser/first_run/try_chrome_dialog_view_browsertest.cc',
       'browser/geolocation/access_token_store_browsertest.cc',
       'browser/geolocation/geolocation_browsertest.cc',
       'browser/history/history_browsertest.cc',
       'browser/history/redirect_browsertest.cc',
       'browser/iframe_browsertest.cc',
+      'browser/image_decoder_browsertest.cc',
       'browser/importer/firefox_importer_browsertest.cc',
       'browser/importer/ie_importer_browsertest_win.cc',
       'browser/importer/importer_unittest_utils.cc',
       'browser/importer/importer_unittest_utils.h',
       'browser/infobars/infobars_browsertest.cc',
       'browser/interstitials/security_interstitial_page_test_utils.cc',
       'browser/interstitials/security_interstitial_page_test_utils.h',
       'browser/invalidation/profile_invalidation_provider_factory_browsertest.cc',
       'browser/lifetime/browser_close_manager_browsertest.cc',
       'browser/loadtimes_extension_bindings_browsertest.cc',
@@ skipping 2923 matching lines @@
             ['enable_webrtc==1', {
               'dependencies': [
                 '../third_party/libjingle/libjingle.gyp:libjingle_webrtc'
               ]
             }],
           ],
         }]
     }],
   ],  # 'conditions'
 }