It turns out the Cleanup() method in JsModalDialog is not

chrome/browser/ui/app_modal_dialogs/js_modal_dialog.cc

Index: chrome/browser/ui/app_modal_dialogs/js_modal_dialog.cc
diff --git a/chrome/browser/ui/app_modal_dialogs/js_modal_dialog.cc b/chrome/browser/ui/app_modal_dialogs/js_modal_dialog.cc
index a1c72f0e8e3dec5a2ef9cd946f2efa57c3d6753b..47d4b82cab0a14d628231dd8923b3a12d9062b07 100644
--- a/chrome/browser/ui/app_modal_dialogs/js_modal_dialog.cc
+++ b/chrome/browser/ui/app_modal_dialogs/js_modal_dialog.cc
@@ -115,8 +115,6 @@ void JavaScriptAppModalDialog::OnCancel(bool suppress_js_messages) {
     if (suppress_js_messages)
       delegate_->SetSuppressMessageBoxes(true);
   }
-
-  Cleanup();
 }
 
 void JavaScriptAppModalDialog::OnAccept(const std::wstring& prompt_text,
@@ -128,28 +126,12 @@ void JavaScriptAppModalDialog::OnAccept(const std::wstring& prompt_text,
     if (suppress_js_messages)
       delegate_->SetSuppressMessageBoxes(true);
   }
-
-  Cleanup();
 }
 
 void JavaScriptAppModalDialog::OnClose() {
-  Cleanup();
-}
-
-void JavaScriptAppModalDialog::Cleanup() {
-  if (skip_this_dialog_) {
-    // We can't use the |delegate_|, because we might be in the process of
-    // destroying it.
-    if (tab_contents_)
-      tab_contents_->OnMessageBoxClosed(reply_msg_, false, L"");
-// The extension_host_ will always be a dirty pointer on OS X because the alert
-// window will cause the extension popup to close since it is resigning its key
-// state, destroying the host. http://crbug.com/29355
-#if !defined(OS_MACOSX)
-    else if (extension_host_)
-      extension_host_->OnMessageBoxClosed(reply_msg_, false, L"");
-    else
-      NOTREACHED();
-#endif
+  if (!skip_this_dialog_) {
+    delegate_->OnMessageBoxClosed(reply_msg_, true, L"");
+    // TODO(aa): It would be good to handle supress here, too, but we need to
+    // get passed the bit.
   }
 }