Add a Cocoa version of the auto-dismissing dialog.

chrome/browser/ui/javascript_dialogs/javascript_dialog.cc

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/ui/javascript_dialogs/javascript_dialog.h"
+
+#include "build/build_config.h"
+#include "chrome/browser/ui/javascript_dialogs/javascript_dialog_views.h"
+
+#if defined(OS_MACOSX)
+#include "chrome/browser/ui/browser_dialogs.h"
+#include "chrome/browser/ui/javascript_dialogs/javascript_dialog_cocoa.h"
+#endif
+
+JavaScriptDialog::~JavaScriptDialog() = default;
+
+base::WeakPtr<JavaScriptDialog> JavaScriptDialog::Create(
+    content::WebContents* parent_web_contents,
+    content::WebContents* alerting_web_contents,
+    const base::string16& title,
+    content::JavaScriptMessageType message_type,
+    const base::string16& message_text,
+    const base::string16& default_prompt_text,
+    const content::JavaScriptDialogManager::DialogClosedCallback&
+        dialog_callback) {
+#if defined(OS_MACOSX)
+  if (chrome::ToolkitViewsWebUIDialogsEnabled()) {
+#endif
+    return JavaScriptDialogViews::Create(
+        parent_web_contents, alerting_web_contents, title, message_type,
+        message_text, default_prompt_text, dialog_callback);
+#if defined(OS_MACOSX)
+  } else {
+    return JavaScriptDialogCocoa::Create(
+        parent_web_contents, alerting_web_contents, title, message_type,
+        message_text, default_prompt_text, dialog_callback);
+  }
+#endif
+}