Reland: Remove "needkey" event and add its replacement, "encrypted".

Source/modules/modules.gypi

 {
   'includes': [
     '../core/core_generated.gypi',
     'modules_generated.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
@@ skipping 14 matching lines @@
       'crypto/Crypto.idl',
       'crypto/CryptoKey.idl',
       'crypto/SubtleCrypto.idl',
       'device_light/DeviceLightEvent.idl',
       'device_orientation/DeviceAcceleration.idl',
       'device_orientation/DeviceMotionEvent.idl',
       'device_orientation/DeviceOrientationEvent.idl',
       'device_orientation/DeviceRotationRate.idl',
       'encoding/TextDecoder.idl',
       'encoding/TextEncoder.idl',
+      'encryptedmedia/MediaEncryptedEvent.idl',
       'encryptedmedia/MediaKeyMessageEvent.idl',
-      'encryptedmedia/MediaKeyNeededEvent.idl',
       'encryptedmedia/MediaKeySession.idl',
       'encryptedmedia/MediaKeys.idl',
       'filesystem/DOMFileSystem.idl',
       'filesystem/DOMFileSystemSync.idl',
       'filesystem/DirectoryEntry.idl',
       'filesystem/DirectoryEntrySync.idl',
       'filesystem/DirectoryReader.idl',
       'filesystem/DirectoryReaderSync.idl',
       'filesystem/EntriesCallback.idl',
       'filesystem/Entry.idl',
@@ skipping 206 matching lines @@
       'vibration/NavigatorVibration.idl',
       'webaudio/WindowWebAudio.idl',
       'webdatabase/WindowWebDatabase.idl',
       'webmidi/NavigatorWebMIDI.idl',
     ],
     # interfaces that inherit from Event
     'modules_event_idl_files': [
       'device_light/DeviceLightEvent.idl',
       'device_orientation/DeviceMotionEvent.idl',
       'device_orientation/DeviceOrientationEvent.idl',
+      'encryptedmedia/MediaEncryptedEvent.idl',
       'encryptedmedia/MediaKeyMessageEvent.idl',
-      'encryptedmedia/MediaKeyNeededEvent.idl',
       'gamepad/GamepadEvent.idl',
       'geofencing/GeofencingEvent.idl',
       'indexeddb/IDBVersionChangeEvent.idl',
       'mediastream/MediaStreamEvent.idl',
       'mediastream/MediaStreamTrackEvent.idl',
       'mediastream/RTCDTMFToneChangeEvent.idl',
       'mediastream/RTCDataChannelEvent.idl',
       'mediastream/RTCIceCandidateEvent.idl',
       'push_messaging/PushEvent.idl',
       'serviceworkers/ExtendableEvent.idl',
@@ skipping 127 matching lines @@
       'device_orientation/DeviceRotationRate.cpp',
       'device_orientation/DeviceRotationRate.h',
       'donottrack/NavigatorDoNotTrack.cpp',
       'donottrack/NavigatorDoNotTrack.h',
       'encoding/TextDecoder.cpp',
       'encoding/TextDecoder.h',
       'encoding/TextEncoder.cpp',
       'encoding/TextEncoder.h',
       'encryptedmedia/HTMLMediaElementEncryptedMedia.cpp',
       'encryptedmedia/HTMLMediaElementEncryptedMedia.h',
+      'encryptedmedia/MediaEncryptedEvent.cpp',
+      'encryptedmedia/MediaEncryptedEvent.h',
       'encryptedmedia/MediaKeyMessageEvent.cpp',
       'encryptedmedia/MediaKeyMessageEvent.h',
-      'encryptedmedia/MediaKeyNeededEvent.cpp',
-      'encryptedmedia/MediaKeyNeededEvent.h',
       'encryptedmedia/MediaKeySession.cpp',
       'encryptedmedia/MediaKeySession.h',
       'encryptedmedia/MediaKeys.cpp',
       'encryptedmedia/MediaKeys.h',
       'encryptedmedia/MediaKeysClient.h',
       'encryptedmedia/MediaKeysController.cpp',
       'encryptedmedia/MediaKeysController.h',
       'encryptedmedia/SimpleContentDecryptionModuleResult.cpp',
       'encryptedmedia/SimpleContentDecryptionModuleResult.h',
       'filesystem/DOMFilePath.cpp',
@@ skipping 629 matching lines @@
       'serviceworkers/ServiceWorkerContainerTest.cpp',
       'websockets/DOMWebSocketTest.cpp',
       'websockets/NewWebSocketChannelImplTest.cpp',
       'websockets/WebSocketDeflaterTest.cpp',
       'websockets/WebSocketExtensionDispatcherTest.cpp',
       'websockets/WebSocketExtensionParserTest.cpp',
       'websockets/WebSocketPerMessageDeflateTest.cpp',
     ],
   },
 }