Issue #1652, #3456 - Replace 's_asyncWebBrowser2' with thread-safe facilities

adblockplus.gyp

 {
   'includes': [
     'defaults.gypi',
     'common/common.gypi',
   ],
 
   'variables': {
     'build_type%': 'devbuild',
     'build_version%': '',
   },
@@ skipping 106 matching lines @@
       'src/plugin/AdblockPlus.rgs',
       'src/plugin/AdblockPlusClient.cpp',
       'src/plugin/AdblockPlusClient.h',
       'src/plugin/AdblockPlusDomTraverser.cpp',
       'src/plugin/AdblockPlusDomTraverser.h',
       'src/plugin/AdblockPlusGuids.h',
       'src/plugin/ATL_Deprecate.cpp',
       'src/plugin/ATL_Deprecate.h',
       'src/plugin/Config.h',
       'src/plugin/Console.h',
+      'src/plugin/Instances.h',
       'src/plugin/NotificationMessage.cpp',
       'src/plugin/NotificationMessage.h',
       'src/plugin/Plugin.cpp',
       'src/plugin/Plugin.h',
       'src/plugin/PluginClass.cpp',
       'src/plugin/PluginClass.h',
       'src/plugin/PluginClientBase.cpp',
       'src/plugin/PluginClientBase.h',
       'src/plugin/PluginClientFactory.cpp',
       'src/plugin/PluginClientFactory.h',
@@ skipping 89 matching lines @@
 
   {
     'target_name': 'tests_plugin',
     'type': 'executable',
     'dependencies': [
       'shared',
       'libadblockplus/libadblockplus.gyp:libadblockplus',
       'libadblockplus/third_party/googletest.gyp:googletest_main',
     ],
     'sources': [
+      'src/plugin/Instances.h',
+      'test/plugin/InstancesTest.cpp',
       'src/plugin/PluginUserSettings.cpp',
       'src/plugin/PluginUserSettings.h',
       'test/plugin/UserSettingsTest.cpp',
       'src/plugin/PluginUtil.h',
       'test/plugin/UtilTest.cpp',
       #
       # required only for linking
       #
       'src/plugin/AdblockPlusClient.cpp',
       'src/plugin/AdblockPlusDomTraverser.cpp',
@@ skipping 35 matching lines @@
           }, {
             'AdditionalLibraryDirectories': [
               '$(ADBLOCKPLUS_ATL)/lib/amd64',
             ],
           }
         ]],
       },
     },
   }]
 }