Improve IDB module's SecurityError messages.

LayoutTests/fast/frames/resources/sandboxed-iframe-storage-disallowed.html

Index: LayoutTests/fast/frames/resources/sandboxed-iframe-storage-disallowed.html
diff --git a/LayoutTests/fast/frames/resources/sandboxed-iframe-storage-disallowed.html b/LayoutTests/fast/frames/resources/sandboxed-iframe-storage-disallowed.html
index 9ff0288260ce40d5d3fa8e78c4664e54b2e3615a..4e609e7f027c55969d8b0e1037c881f9268aba06 100644
--- a/LayoutTests/fast/frames/resources/sandboxed-iframe-storage-disallowed.html
+++ b/LayoutTests/fast/frames/resources/sandboxed-iframe-storage-disallowed.html
@@ -55,6 +55,9 @@ function shouldThrow(_a, _e)
 
 window.onload = function() {
     shouldThrow("window.openDatabase('SandboxedIframeStorageDisallowed', '1.0', '', 1)");
+    shouldThrow("window.indexedDB.webkitGetDatabaseNames()", '"SecurityError: Failed to execute \'getDatabaseNames\' on \'IDBFactory\': access to the Indexed Database API is denied in this context."');
+    shouldThrow("window.indexedDB.open('foo')", '"SecurityError: Failed to execute \'open\' on \'IDBFactory\': access to the Indexed Database API is denied in this context."');
+    shouldThrow("window.indexedDB.deleteDatabase('foo')", '"SecurityError: Failed to execute \'deleteDatabase\' on \'IDBFactory\': access to the Indexed Database API is denied in this context."');
     shouldThrow("window.localStorage", '"SecurityError: Access to \'localStorage\' is denied for this document. The document is sandboxed and lacks the \'allow-same-origin\' flag."');
     shouldThrow("window.sessionStorage", '"SecurityError: Access to \'sessionStorage\' is denied for this document. The document is sandboxed and lacks the \'allow-same-origin\' flag."');
     shouldThrow("document.cookie",'"SecurityError: Access to \'cookie\' is denied for this document. The document is sandboxed and lacks the \'allow-same-origin\' flag."') ;