[InputEvent] Add InputEvent with basic interface behind a flag

third_party/WebKit/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 112 matching lines @@
             'events/BeforeUnloadEvent.idl',
             'events/ClipboardEvent.idl',
             'events/CompositionEvent.idl',
             'events/CustomEvent.idl',
             'events/DragEvent.idl',
             'events/ErrorEvent.idl',
             'events/Event.idl',
             'events/EventTarget.idl',
             'events/FocusEvent.idl',
             'events/HashChangeEvent.idl',
+            'events/InputEvent.idl',
             'events/KeyboardEvent.idl',
             'events/MessageEvent.idl',
             'events/MutationEvent.idl',
             'events/PageTransitionEvent.idl',
             'events/PointerEvent.idl',
             'events/PopStateEvent.idl',
             'events/ProgressEvent.idl',
             'events/PromiseRejectionEvent.idl',
             'events/RelatedEvent.idl',
             'events/ResourceProgressEvent.idl',
@@ skipping 323 matching lines @@
             'events/AutocompleteErrorEvent.idl',
             'events/BeforeUnloadEvent.idl',
             'events/ClipboardEvent.idl',
             'events/CompositionEvent.idl',
             'events/CustomEvent.idl',
             'events/DragEvent.idl',
             'events/ErrorEvent.idl',
             'events/Event.idl',
             'events/FocusEvent.idl',
             'events/HashChangeEvent.idl',
+            'events/InputEvent.idl',
             'events/KeyboardEvent.idl',
             'events/MessageEvent.idl',
             'events/MouseEvent.idl',
             'events/MutationEvent.idl',
             'events/PageTransitionEvent.idl',
             'events/PointerEvent.idl',
             'events/PopStateEvent.idl',
             'events/ProgressEvent.idl',
             'events/PromiseRejectionEvent.idl',
             'events/RelatedEvent.idl',
@@ skipping 2207 matching lines @@
             'events/EventQueue.h',
             'events/EventSender.h',
             'events/EventTarget.cpp',
             'events/FocusEvent.cpp',
             'events/FocusEvent.h',
             'events/GenericEventQueue.cpp',
             'events/GenericEventQueue.h',
             'events/GestureEvent.cpp',
             'events/GestureEvent.h',
             'events/HashChangeEvent.h',
+            'events/InputEvent.cpp',
+            'events/InputEvent.h',
             'events/KeyboardEvent.cpp',
             'events/MessageEvent.cpp',
             'events/MessageEvent.h',
             'events/MouseEvent.cpp',
             'events/MouseRelatedEvent.cpp',
             'events/MutationEvent.cpp',
             'events/MutationEvent.h',
             'events/NavigatorEvents.cpp',
             'events/NavigatorEvents.h',
             'events/NodeEventContext.cpp',
@@ skipping 930 matching lines @@
             'events/AutocompleteErrorEventInit.idl',
             'events/CompositionEventInit.idl',
             'events/CustomEventInit.idl',
             'events/DragEventInit.idl',
             'events/ErrorEventInit.idl',
             'events/EventInit.idl',
             'events/EventListenerOptions.idl',
             'events/EventModifierInit.idl',
             'events/FocusEventInit.idl',
             'events/HashChangeEventInit.idl',
+            'events/InputEventInit.idl',
             'events/KeyboardEventInit.idl',
             'events/MessageEventInit.idl',
             'events/MouseEventInit.idl',
             'events/PageTransitionEventInit.idl',
             'events/PointerEventInit.idl',
             'events/PopStateEventInit.idl',
             'events/ProgressEventInit.idl',
             'events/PromiseRejectionEventInit.idl',
             'events/RelatedEventInit.idl',
             'events/SecurityPolicyViolationEventInit.idl',
@@ skipping 60 matching lines @@
             '<(blink_core_output_dir)/events/EventInit.cpp',
             '<(blink_core_output_dir)/events/EventInit.h',
             '<(blink_core_output_dir)/events/EventListenerOptions.cpp',
             '<(blink_core_output_dir)/events/EventListenerOptions.h',
             '<(blink_core_output_dir)/events/EventModifierInit.cpp',
             '<(blink_core_output_dir)/events/EventModifierInit.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/InputEventInit.cpp',
+            '<(blink_core_output_dir)/events/InputEventInit.h',
             '<(blink_core_output_dir)/events/KeyboardEventInit.cpp',
             '<(blink_core_output_dir)/events/KeyboardEventInit.h',
             '<(blink_core_output_dir)/events/MessageEventInit.cpp',
             '<(blink_core_output_dir)/events/MessageEventInit.h',
             '<(blink_core_output_dir)/events/MouseEventInit.cpp',
             '<(blink_core_output_dir)/events/MouseEventInit.h',
             '<(blink_core_output_dir)/events/PageTransitionEventInit.cpp',
             '<(blink_core_output_dir)/events/PageTransitionEventInit.h',
             '<(blink_core_output_dir)/events/PointerEventInit.cpp',
             '<(blink_core_output_dir)/events/PointerEventInit.h',
@@ skipping 315 matching lines @@
             'style/SVGComputedStyleTest.cpp',
             'svg/SVGPathParserTest.cpp',
             'svg/UnsafeSVGAttributeSanitizationTest.cpp',
             'testing/PrivateScriptTestTest.cpp',
             'timing/MemoryInfoTest.cpp',
             'workers/WorkerThreadTest.cpp',
             'xml/parser/SharedBufferReaderTest.cpp',
         ],
     }
 }