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

LayoutTests/media/encrypted-media/encrypted-media-waiting-for-a-key.html

Index: LayoutTests/media/encrypted-media/encrypted-media-waiting-for-a-key.html
diff --git a/LayoutTests/media/encrypted-media/encrypted-media-waiting-for-a-key.html b/LayoutTests/media/encrypted-media/encrypted-media-waiting-for-a-key.html
index 49bca629f83a4ee48b0167a652e53024f0fffa84..a94f4a4e350aa8c3f05540e9da00b01cb165b239 100644
--- a/LayoutTests/media/encrypted-media/encrypted-media-waiting-for-a-key.html
+++ b/LayoutTests/media/encrypted-media/encrypted-media-waiting-for-a-key.html
@@ -21,11 +21,11 @@
                 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.
@@ -35,7 +35,7 @@
 
                     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);
                     });
                 }
@@ -89,7 +89,7 @@
                 }
 
                 MediaKeys.create('org.w3.clearkey').then(function(mediaKeys) {
-                    waitForEventAndRunStep('needkey', video, onNeedKey, test);
+                    waitForEventAndRunStep('encrypted', video, onEncrypted, test);
                     waitForEventAndRunStep('playing', video, onPlaying, test);
                     video.src = '../content/test-encrypted.webm';
                     return video.setMediaKeys(mediaKeys);