Implement onunhandledrejection / onrejectionhandled events

LayoutTests/webexposed/global-interface-listing-expected.txt

Index: LayoutTests/webexposed/global-interface-listing-expected.txt
diff --git a/LayoutTests/webexposed/global-interface-listing-expected.txt b/LayoutTests/webexposed/global-interface-listing-expected.txt
index 9dfaf030bf59b7e81b38b51e3f4bf110e292cdc4..8808c39bf266a3e438654086e132d73c597d6c79 100644
--- a/LayoutTests/webexposed/global-interface-listing-expected.txt
+++ b/LayoutTests/webexposed/global-interface-listing-expected.txt
@@ -1710,9 +1710,11 @@ interface HTMLBodyElement
     getter onpagehide
     getter onpageshow
     getter onpopstate
+    getter onrejectionhandled
     getter onresize
     getter onscroll
     getter onstorage
+    getter onunhandledrejection
     getter onunload
     getter text
     getter vLink
@@ -1734,9 +1736,11 @@ interface HTMLBodyElement
     setter onpagehide
     setter onpageshow
     setter onpopstate
+    setter onrejectionhandled
     setter onresize
     setter onscroll
     setter onstorage
+    setter onunhandledrejection
     setter onunload
     setter text
     setter vLink
@@ -3771,6 +3775,10 @@ interface Promise
     method chain
     method constructor
     method then
+interface PromiseRejectionEvent
+    getter promise
+    getter reason
+    method constructor
 interface PushManager
     method constructor
     method getSubscription
@@ -6342,6 +6350,7 @@ interface Window
     attribute onpopstate
     attribute onprogress
     attribute onratechange
+    attribute onrejectionhandled
     attribute onreset
     attribute onresize
     attribute onscroll
@@ -6361,6 +6370,7 @@ interface Window
     attribute ontouchmove
     attribute ontouchstart
     attribute ontransitionend
+    attribute onunhandledrejection
     attribute onunload
     attribute onvolumechange
     attribute onwaiting