Throw exceptions on all failed cross-origin access checks.

LayoutTests/http/tests/history/cross-origin-replace-history-object-child.html

Index: LayoutTests/http/tests/history/cross-origin-replace-history-object-child.html
diff --git a/LayoutTests/http/tests/history/cross-origin-replace-history-object-child.html b/LayoutTests/http/tests/history/cross-origin-replace-history-object-child.html
index 7e83528d10b1a64ad59457ef646d0430f83d8787..ec6b1ed98be3dad935929e5304607c115c0f8771 100644
--- a/LayoutTests/http/tests/history/cross-origin-replace-history-object-child.html
+++ b/LayoutTests/http/tests/history/cross-origin-replace-history-object-child.html
@@ -14,14 +14,21 @@ window.onmessage = function(evt)
         testRunner.notifyDone();
         return;
     }
-
-    alert("Child window's history object after attempt to clear: " + window.frames[0].history);
+    try {
+        alert("Child window's history object after attempt to clear: " + window.frames[0].history);
+    } catch (e) {
+        alert("PASS: Access to window.frames[0].history threw an exception.");
+    }
     testRunner.notifyDone();
 }
 
 function setHistoryLength()
 {
-    alert("Child window's history object before attempt to clear: " + window.frames[0].history);
+    try {
+        alert("Child window's history object before attempt to clear: " + window.frames[0].history);
+    } catch (e) {
+        alert("PASS: Access to window.frames[0].history threw an exception.");
+    }
     window.frames[0].postMessage("setHistoryLength", "*");
 }