WebUI: Add JavaScript lifecycle-control to WebUIMessageHandler.

chrome/browser/ui/webui/settings/settings_startup_pages_handler.cc

 // Copyright 2015 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/webui/settings/settings_startup_pages_handler.h"
 
 #include <string>
 #include <vector>
 
 #include "chrome/browser/prefs/session_startup_pref.h"
@@ skipping 29 matching lines @@
       base::Bind(&StartupPagesHandler::HandleRemoveStartupPage,
                  base::Unretained(this)));
   web_ui()->RegisterMessageCallback("setStartupPagesToCurrentPages",
       base::Bind(&StartupPagesHandler::HandleSetStartupPagesToCurrentPages,
                  base::Unretained(this)));
   web_ui()->RegisterMessageCallback("validateStartupPage",
       base::Bind(&StartupPagesHandler::HandleValidateStartupPage,
                  base::Unretained(this)));
 }
 
-void StartupPagesHandler::RenderViewReused() {
+void StartupPagesHandler::OnJavascriptAllowed() {
+  startup_custom_pages_table_model_.SetObserver(this);
+
+  PrefService* prefService = Profile::FromWebUI(web_ui())->GetPrefs();
+  SessionStartupPref pref = SessionStartupPref::GetStartupPref(
+      prefService);
+  startup_custom_pages_table_model_.SetURLs(pref.urls);
+
+  if (pref.urls.empty())
+    pref.type = SessionStartupPref::DEFAULT;
+
+  pref_change_registrar_.Init(prefService);
+  pref_change_registrar_.Add(
+      prefs::kURLsToRestoreOnStartup,
+      base::Bind(&StartupPagesHandler::UpdateStartupPages,
+                 base::Unretained(this)));
+}
+
+void StartupPagesHandler::OnJavascriptDisallowed() {
   startup_custom_pages_table_model_.SetObserver(nullptr);
   pref_change_registrar_.RemoveAll();
 }
 
 void StartupPagesHandler::OnModelChanged() {
   base::ListValue startup_pages;
   int page_count = startup_custom_pages_table_model_.RowCount();
   std::vector<GURL> urls = startup_custom_pages_table_model_.GetURLs();
   for (int i = 0; i < page_count; ++i) {
     std::unique_ptr<base::DictionaryValue> entry(new base::DictionaryValue());
     entry->SetString("title", startup_custom_pages_table_model_.GetText(i, 0));
     entry->SetString("url", urls[i].spec());
     entry->SetString("tooltip",
                      startup_custom_pages_table_model_.GetTooltip(i));
     entry->SetInteger("modelIndex", i);
     startup_pages.Append(entry.release());
   }
 
-  web_ui()->CallJavascriptFunction("cr.webUIListenerCallback",
-                                   base::StringValue("update-startup-pages"),
-                                   startup_pages);
+  CallJavascriptFunction("cr.webUIListenerCallback",
+                         base::StringValue("update-startup-pages"),
+                         startup_pages);
 }
 
 void StartupPagesHandler::OnItemsChanged(int start, int length) {
   OnModelChanged();
 }
 
 void StartupPagesHandler::OnItemsAdded(int start, int length) {
   OnModelChanged();
 }
 
@@ skipping 49 matching lines @@
     startup_custom_pages_table_model_.SetURLs(urls);
     SaveStartupPagesPref();
     ResolveJavascriptCallback(*callback_id, base::FundamentalValue(true));
   } else {
     ResolveJavascriptCallback(*callback_id, base::FundamentalValue(false));
   }
 }
 
 void StartupPagesHandler::HandleOnStartupPrefsPageLoad(
     const base::ListValue* args) {
-  startup_custom_pages_table_model_.SetObserver(this);
-
-  PrefService* prefService = Profile::FromWebUI(web_ui())->GetPrefs();
-  SessionStartupPref pref = SessionStartupPref::GetStartupPref(
-      prefService);
-  startup_custom_pages_table_model_.SetURLs(pref.urls);
-
-  if (pref.urls.empty())
-    pref.type = SessionStartupPref::DEFAULT;
-
-  pref_change_registrar_.Init(prefService);
-  pref_change_registrar_.Add(
-      prefs::kURLsToRestoreOnStartup,
-      base::Bind(&StartupPagesHandler::UpdateStartupPages,
-                 base::Unretained(this)));
-
-  const SessionStartupPref startup_pref = SessionStartupPref::GetStartupPref(
-      Profile::FromWebUI(web_ui())->GetPrefs());
-  startup_custom_pages_table_model_.SetURLs(startup_pref.urls);
+  AllowJavascript();
 }
 
 void StartupPagesHandler::HandleRemoveStartupPage(const base::ListValue* args) {
   int selected_index;
   if (!args->GetInteger(0, &selected_index)) {
     NOTREACHED();
     return;
   }
 
   if (selected_index < 0 ||
@@ skipping 40 matching lines @@
 
 void StartupPagesHandler::UpdateStartupPages() {
   const SessionStartupPref startup_pref = SessionStartupPref::GetStartupPref(
       Profile::FromWebUI(web_ui())->GetPrefs());
   startup_custom_pages_table_model_.SetURLs(startup_pref.urls);
   // The change will go to the JS code in the
   // StartupPagesHandler::OnModelChanged() method.
 }
 
 }  // namespace settings