Add a JavaScript dialog tab helper.

chrome/browser/ui/javascript_dialogs/javascript_dialog_tab_helper.cc

Index: chrome/browser/ui/javascript_dialogs/javascript_dialog_tab_helper.cc
diff --git a/chrome/browser/ui/javascript_dialogs/javascript_dialog_tab_helper.cc b/chrome/browser/ui/javascript_dialogs/javascript_dialog_tab_helper.cc
new file mode 100644
index 0000000000000000000000000000000000000000..86199c0a73b23835851d915851406c43bc56f667
--- /dev/null
+++ b/chrome/browser/ui/javascript_dialogs/javascript_dialog_tab_helper.cc
@@ -0,0 +1,97 @@
+// 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_tab_helper.h"
+
+#include "base/feature_list.h"
+#include "components/app_modal/javascript_dialog_manager.h"
+
+DEFINE_WEB_CONTENTS_USER_DATA_KEY(JavaScriptDialogTabHelper);
+
+namespace {
+
+const base::Feature kAutoDismissingDialogsFeature{
+    "AutoDismissingDialogs", base::FEATURE_DISABLED_BY_DEFAULT};
+
+bool IsEnabled() {
+  return base::FeatureList::IsEnabled(kAutoDismissingDialogsFeature);
+}
+
+content::JavaScriptDialogManager* AppModalDialogManager() {
+  return app_modal::JavaScriptDialogManager::GetInstance();
+}
+
+}  // namespace
+
+JavaScriptDialogTabHelper::JavaScriptDialogTabHelper(
+    content::WebContents* web_contents)
+    : content::WebContentsObserver(web_contents) {
+}
+
+JavaScriptDialogTabHelper::~JavaScriptDialogTabHelper() {
+}
+
+void JavaScriptDialogTabHelper::WebContentsDestroyed() {
+}
+
+void JavaScriptDialogTabHelper::RunJavaScriptDialog(
+    content::WebContents* web_contents,
+    const GURL& origin_url,
+    content::JavaScriptMessageType message_type,
+    const base::string16& message_text,
+    const base::string16& default_prompt_text,
+    const DialogClosedCallback& callback,
+    bool* did_suppress_message) {
+  if (!IsEnabled()) {
+    return AppModalDialogManager()->RunJavaScriptDialog(
+        web_contents, origin_url, message_type, message_text,
+        default_prompt_text, callback, did_suppress_message);
+  }
+
+  NOTREACHED() << "auto-dismissing dialog code does not yet exist";
+}
+
+void JavaScriptDialogTabHelper::RunBeforeUnloadDialog(
+    content::WebContents* web_contents,
+    bool is_reload,
+    const DialogClosedCallback& callback) {
+  // onbeforeunload dialogs are always handled with an app-modal dialog, because
+  // - they are critical to the user not losing data
+  // - they can be requested for tabs that are not foremost
+  // - they can be requested for many tabs at the same time
+  // and therefore auto-dismissal is inappropriate for them.
+
+  return AppModalDialogManager()->RunBeforeUnloadDialog(web_contents, is_reload,
+                                                        callback);
+}
+
+bool JavaScriptDialogTabHelper::HandleJavaScriptDialog(
+    content::WebContents* web_contents,
+    bool accept,
+    const base::string16* prompt_override) {
+  if (!IsEnabled()) {
+    return AppModalDialogManager()->HandleJavaScriptDialog(web_contents, accept,
+                                                           prompt_override);
+  }
+
+  NOTREACHED() << "auto-dismissing dialog code does not yet exist";
+  return false;
+}
+
+void JavaScriptDialogTabHelper::CancelActiveAndPendingDialogs(
+    content::WebContents* web_contents) {
+  // Cancel any app-modal dialogs that may be going.
+  AppModalDialogManager()->CancelActiveAndPendingDialogs(web_contents);
+
+  // More work here for the auto-dismissing dialogs.
+}
+
+void JavaScriptDialogTabHelper::ResetDialogState(
+    content::WebContents* web_contents) {
+  // Reset any app-modal dialog state that may exist.
+  if (!IsEnabled())
+    return AppModalDialogManager()->ResetDialogState(web_contents);
+
+  // More work here for the auto-dismissing dialogs.
+}