Make EventInterfaces.in build step not depend on bindings generation

Source/modules/modules.gypi

 {
   'variables': {
     # Experimental hooks for embedder to provide extra IDL and source files.
     #
     # Note: this is not a supported API. If you rely on this, you will be broken
     # from time to time as the code generator changes in backward incompatible
     # ways.
     'extra_blink_module_idl_files': [],
     'extra_blink_module_files': [],
     # Files for which bindings (.cpp and .h files) will be generated
@@ skipping 208 matching lines @@
       'quota/WindowQuota.idl',
       'quota/WorkerNavigatorStorageQuota.idl',
       'screen_orientation/ScreenOrientation.idl',
       'serviceworkers/NavigatorServiceWorker.idl',
       'speech/WindowSpeechSynthesis.idl',
       'vibration/NavigatorVibration.idl',
       'webdatabase/WindowWebDatabase.idl',
       'webdatabase/WorkerGlobalScopeWebDatabase.idl',
       'webmidi/NavigatorWebMIDI.idl',
     ],
+    # interfaces that inherit from Event
+    'modules_event_idl_files': [
+      'device_orientation/DeviceMotionEvent.idl',
+      'device_orientation/DeviceOrientationEvent.idl',
+      'encryptedmedia/MediaKeyMessageEvent.idl',
+      'encryptedmedia/MediaKeyNeededEvent.idl',
+      'gamepad/GamepadEvent.idl',
+      'indexeddb/IDBVersionChangeEvent.idl',
+      'mediastream/MediaStreamEvent.idl',
+      'mediastream/MediaStreamTrackEvent.idl',
+      'mediastream/RTCDTMFToneChangeEvent.idl',
+      'mediastream/RTCDataChannelEvent.idl',
+      'mediastream/RTCIceCandidateEvent.idl',
+      'serviceworkers/FetchEvent.idl',
+      'serviceworkers/InstallEvent.idl',
+      'serviceworkers/InstallPhaseEvent.idl',
+      'speech/SpeechRecognitionError.idl',
+      'speech/SpeechRecognitionEvent.idl',
+      'speech/SpeechSynthesisEvent.idl',
+      'webaudio/AudioProcessingEvent.idl',
+      'webaudio/OfflineAudioCompletionEvent.idl',
+      'webmidi/MIDIConnectionEvent.idl',
+      'webmidi/MIDIMessageEvent.idl',
+      'websockets/CloseEvent.idl',
+    ],
     'modules_files': [
       '<@(extra_blink_module_files)',
       'battery/BatteryManager.cpp',
       'battery/BatteryManager.h',
       'battery/BatteryStatus.cpp',
       'battery/BatteryStatus.h',
       'battery/NavigatorBattery.cpp',
       'battery/NavigatorBattery.h',
       'crypto/Crypto.cpp',
       'crypto/Crypto.h',
@@ skipping 648 matching lines @@
       'indexeddb/IDBKeyPathTest.cpp',
       'indexeddb/IDBRequestTest.cpp',
       'indexeddb/IDBTransactionTest.cpp',
       'websockets/WebSocketDeflaterTest.cpp',
       'websockets/WebSocketExtensionDispatcherTest.cpp',
       'websockets/WebSocketExtensionParserTest.cpp',
       'websockets/WebSocketPerMessageDeflateTest.cpp',
     ],
   },
 }