Bug 1834519 - Don't throw when popovers/dialogs are in requested state. r=emilio

Update to be in line with spec discussions at
whatwg/html#9142

Differential Revision: https://phabricator.services.mozilla.com/D178782

UltraBlame original commit: 39007d3d4f3eee8382115fb59e595de006ceca70

Author: marco-c

dom/html/HTMLDialogElement.cpp

@@ -412,7 +412,36 @@ Open
 )
 )
 {
+if
+(
+!
+IsInTopLayer
+(
+)
+)
+{
+return
+;
+}
 return
+aError
+.
+ThrowInvalidStateError
+(
+"
+Cannot
+call
+show
+(
+)
+on
+an
+open
+modal
+dialog
+.
+"
+)
 ;
 }
 if
@@ -632,30 +661,48 @@ aError
 {
 if
 (
-!
-IsInComposedDoc
+Open
+(
+)
+)
+{
+if
+(
+IsInTopLayer
 (
 )
 )
 {
 return
+;
+}
+return
 aError
 .
 ThrowInvalidStateError
 (
 "
-Dialog
-element
-is
-not
-connected
+Cannot
+call
+showModal
+(
+)
+on
+an
+open
+non
+-
+modal
+dialog
+.
 "
 )
 ;
 }
 if
 (
-Open
+!
+IsInComposedDoc
 (
 )
 )
@@ -668,13 +715,9 @@ ThrowInvalidStateError
 "
 Dialog
 element
-already
-has
-an
-'
-open
-'
-attribute
+is
+not
+connected
 "
 )
 ;