DOMException toString is not correct

LayoutTests/fast/dom/Window/window-postmessage-clone-expected.txt

Index: LayoutTests/fast/dom/Window/window-postmessage-clone-expected.txt
diff --git a/LayoutTests/fast/dom/Window/window-postmessage-clone-expected.txt b/LayoutTests/fast/dom/Window/window-postmessage-clone-expected.txt
index fcc5fe77bb4678a64c91101f223e78a3b169f3c8..abd99500e8b33f8a6717da9e6f60b15340660ae1 100644
--- a/LayoutTests/fast/dom/Window/window-postmessage-clone-expected.txt
+++ b/LayoutTests/fast/dom/Window/window-postmessage-clone-expected.txt
@@ -1,8 +1,8 @@
 Tests that we clone object hierarchies
 
-PASS: 'postMessage((function(){}))' threw Error: DataCloneError: DOM Exception 25
-PASS: 'postMessage(var x = 0; try { eval("badref"); } catch(e) { x = e; } x)' threw Error: DataCloneError: DOM Exception 25
-PASS: 'postMessage(window)' threw Error: DataCloneError: DOM Exception 25
+PASS: 'postMessage((function(){}))' threw DataCloneError: An object could not be cloned.
+PASS: 'postMessage(var x = 0; try { eval("badref"); } catch(e) { x = e; } x)' threw DataCloneError: An object could not be cloned.
+PASS: 'postMessage(window)' threw DataCloneError: An object could not be cloned.
 PASS: 'postMessage(({get a() { throw "x" }}))' threw x
 PASS: 'postMessage((function() {return {get a() { throw "accessor-exn"; }};})())' threw accessor-exn
 PASS: 'postMessage((function() {var obja = {get p() { throw "accessor-exn"; }}; return {get a() { return obja; }};})())' threw accessor-exn
@@ -132,7 +132,7 @@ PASS: FileList should not respect reference equality (0)
 PASS: FileList should not respect reference equality (1)
 PASS: FileList preserves order and data (name0)
 PASS: FileList preserves order and data (name1)
-PASS: FileList preserves order and data (date0)
+FAIL: FileList preserves order and data (date0)
 PASS: FileList preserves order and data (date1)
 PASS: eventData is done of type string