Remove left-overs of PushSubscription.curve25519dh

Source/modules/push_messaging/PushSubscription.idl

Index: Source/modules/push_messaging/PushSubscription.idl
diff --git a/Source/modules/push_messaging/PushSubscription.idl b/Source/modules/push_messaging/PushSubscription.idl
index 57946a67db5d0f834f2e7d5f0d1907aa5c0055b3..a1ed1a2c91b65dfee77fc945a963750958f5867c 100644
--- a/Source/modules/push_messaging/PushSubscription.idl
+++ b/Source/modules/push_messaging/PushSubscription.idl
@@ -15,9 +15,6 @@ enum PushEncryptionKeyName {
 ] interface PushSubscription {
     readonly attribute USVString endpoint;
 
-    // TODO(peter): Remove this once the embedder updates to getKey().
-    [RuntimeEnabled=PushMessagingData] readonly attribute ArrayBuffer curve25519dh;
-
     [RuntimeEnabled=PushMessagingData] ArrayBuffer? getKey(PushEncryptionKeyName name);
     [CallWith=ScriptState] Promise<boolean> unsubscribe();