Introduce XMLHttpRequestEventTarget IDL interface

Source/core/core.gypi

 {
     'variables': {
         'deprecated_perl_core_idl_files': [
             'css/CSS.idl',
             'css/CSSCharsetRule.idl',
             'css/CSSFontFaceLoadEvent.idl',
             'css/CSSFontFaceRule.idl',
             'css/CSSHostRule.idl',
             'css/CSSImportRule.idl',
             'css/CSSMediaRule.idl',
@@ skipping 257 matching lines @@
             'storage/Storage.idl',
             'storage/StorageEvent.idl',
             'workers/DedicatedWorkerGlobalScope.idl',
             'workers/SharedWorker.idl',
             'workers/SharedWorkerGlobalScope.idl',
             'workers/Worker.idl',
             'workers/WorkerGlobalScope.idl',
             'workers/WorkerLocation.idl',
             'xml/DOMParser.idl',
             'xml/XMLHttpRequest.idl',
+            'xml/XMLHttpRequestEventTarget.idl',
             'xml/XMLHttpRequestProgressEvent.idl',
             'xml/XMLHttpRequestUpload.idl',
             'xml/XMLSerializer.idl',
             'xml/XPathEvaluator.idl',
             'xml/XPathExpression.idl',
             'xml/XPathNSResolver.idl',
             'xml/XPathResult.idl',
             'xml/XSLTProcessor.idl',
         ],
         'python_core_idl_files': [
@@ skipping 1362 matching lines @@
             'xml/DocumentXPathEvaluator.cpp',
             'xml/DocumentXPathEvaluator.h',
             'xml/DOMParser.cpp',
             'xml/DOMParser.h',
             'xml/NativeXPathNSResolver.cpp',
             'xml/NativeXPathNSResolver.h',
             'xml/XMLErrors.cpp',
             'xml/XMLErrors.h',
             'xml/XMLHttpRequest.cpp',
             'xml/XMLHttpRequest.h',
+            'xml/XMLHttpRequestEventTarget.h',
             'xml/XMLHttpRequestProgressEvent.h',
             'xml/XMLHttpRequestProgressEventThrottle.cpp',
             'xml/XMLHttpRequestProgressEventThrottle.h',
             'xml/XMLHttpRequestUpload.cpp',
             'xml/XMLHttpRequestUpload.h',
             'xml/XMLSerializer.cpp',
             'xml/XMLSerializer.h',
             'xml/XMLTreeViewer.cpp',
             'xml/XMLTreeViewer.h',
             'xml/XPathEvaluator.cpp',
@@ skipping 2158 matching lines @@
                 'bison_exe': 'bison',
                 # We specify a preprocess so it happens locally and won't get
                 # distributed to goma.
                 # FIXME: /usr/bin/gcc won't exist on OSX forever. We want to
                 # use /usr/bin/clang once we require Xcode 4.x.
                 'preprocessor': '--preprocessor "/usr/bin/gcc -E -P -x c++"'
               }],
          ],
     }
 }