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

LayoutTests/media/encrypted-media/encrypted-media-playback-setmediakeys-before-src.html

Index: LayoutTests/media/encrypted-media/encrypted-media-playback-setmediakeys-before-src.html
diff --git a/LayoutTests/media/encrypted-media/encrypted-media-playback-setmediakeys-before-src.html b/LayoutTests/media/encrypted-media/encrypted-media-playback-setmediakeys-before-src.html
index 17f8d5a5569668b4244374e8b11b7eba0a36a50b..036b48ddf250819ea18b7e7a4d48542a54140c6b 100644
--- a/LayoutTests/media/encrypted-media/encrypted-media-playback-setmediakeys-before-src.html
+++ b/LayoutTests/media/encrypted-media/encrypted-media-playback-setmediakeys-before-src.html
@@ -20,11 +20,11 @@
                 var rawKey = new Uint8Array([0xeb, 0xdd, 0x62, 0xf1, 0x68, 0x14, 0xd2, 0x7b,
                                              0x68, 0xef, 0x12, 0x2a, 0xfc, 0xe4, 0xae, 0x3c]);
 
-                function onNeedKey(event)
+                function onEncrypted(event)
                 {
                     assert_equals(event.target, video);
-                    assert_true(event instanceof window.MediaKeyNeededEvent);
-                    assert_equals(event.type, 'needkey');
+                    assert_true(event instanceof window.MediaEncryptedEvent);
+                    assert_equals(event.type, 'encrypted');
 
                     // The same decryption key is shared by all streams so only create a shared session once.
                     if (isSessionCreated)
@@ -33,7 +33,7 @@
 
                     var mediaKeySession = video.mediaKeys.createSession();
                     waitForEventAndRunStep('message', mediaKeySession, onMessage, test);
-                    mediaKeySession.generateRequest(event.contentType, event.initData).catch(function(error) {
+                    mediaKeySession.generateRequest(event.initDataType, event.initData).catch(function(error) {
                         forceTestFailureFromPromise(test, error);
                     });
                 }
@@ -69,7 +69,7 @@
 
                 MediaKeys.create('org.w3.clearkey').then(function(mediaKeys) {
 
-                    waitForEventAndRunStep('needkey', video, onNeedKey, test);
+                    waitForEventAndRunStep('encrypted', video, onEncrypted, test);
                     waitForEventAndRunStep('playing', video, onPlaying, test);
 
                     return video.setMediaKeys(mediaKeys);