IDL: Add any support to IDL dictionary and use it in CustomEventInit

Source/core/core.gypi

 {
     'includes': [
         'core_generated.gypi',
     ],
     'variables': {
         # Files for which bindings (.cpp and .h files) will be generated
         'core_idl_files': [
             'animation/KeyframeEffect.idl',
             'animation/EffectModel.idl',
             'animation/AnimationEffectReadOnly.idl',
@@ skipping 3550 matching lines @@
             'css/FontFaceDescriptors.idl',
             'css/MediaQueryListEventInit.idl',
             'dom/DOMPointInit.idl',
             'dom/ElementRegistrationOptions.idl',
             'dom/MutationObserverInit.idl',
             'events/AnimationEventInit.idl',
             'events/AnimationPlayerEventInit.idl',
             'events/ApplicationCacheErrorEventInit.idl',
             'events/AutocompleteErrorEventInit.idl',
             'events/CompositionEventInit.idl',
+            'events/CustomEventInit.idl',
             'events/EventInit.idl',
             'events/FocusEventInit.idl',
             'events/HashChangeEventInit.idl',
             'events/KeyboardEventInit.idl',
             'events/MouseEventInit.idl',
             'events/OverflowEventInit.idl',
             'events/PageTransitionEventInit.idl',
             'events/PointerEventInit.idl',
             'events/ProgressEventInit.idl',
             'events/RelatedEventInit.idl',
@@ skipping 34 matching lines @@
             '<(blink_core_output_dir)/events/AnimationEventInit.cpp',
             '<(blink_core_output_dir)/events/AnimationEventInit.h',
             '<(blink_core_output_dir)/events/AnimationPlayerEventInit.cpp',
             '<(blink_core_output_dir)/events/AnimationPlayerEventInit.h',
             '<(blink_core_output_dir)/events/ApplicationCacheErrorEventInit.cpp',
             '<(blink_core_output_dir)/events/ApplicationCacheErrorEventInit.h',
             '<(blink_core_output_dir)/events/AutocompleteErrorEventInit.cpp',
             '<(blink_core_output_dir)/events/AutocompleteErrorEventInit.h',
             '<(blink_core_output_dir)/events/CompositionEventInit.cpp',
             '<(blink_core_output_dir)/events/CompositionEventInit.h',
+            '<(blink_core_output_dir)/events/CustomEventInit.cpp',
+            '<(blink_core_output_dir)/events/CustomEventInit.h',
             '<(blink_core_output_dir)/events/EventInitDictionary.cpp',
             '<(blink_core_output_dir)/events/EventInitDictionary.h',
             '<(blink_core_output_dir)/events/FocusEventInit.cpp',
             '<(blink_core_output_dir)/events/FocusEventInit.h',
             '<(blink_core_output_dir)/events/HashChangeEventInit.cpp',
             '<(blink_core_output_dir)/events/HashChangeEventInit.h',
             '<(blink_core_output_dir)/events/KeyboardEventInit.cpp',
             '<(blink_core_output_dir)/events/KeyboardEventInit.h',
             '<(blink_core_output_dir)/events/MouseEventInit.cpp',
             '<(blink_core_output_dir)/events/MouseEventInit.h',
@@ skipping 259 matching lines @@
             'style/ComputedStyleTest.cpp',
             'style/OutlineValueTest.cpp',
             'style/SVGComputedStyleTest.cpp',
             'testing/PrivateScriptTestTest.cpp',
             'timing/MemoryInfoTest.cpp',
             'workers/WorkerThreadTest.cpp',
             'xml/parser/SharedBufferReaderTest.cpp',
         ],
     }
 }