Revert of Revert "Typecheck JS files for chrome://extensions"

chrome/browser/ui/webui/extensions/extension_settings_handler.cc

Index: chrome/browser/ui/webui/extensions/extension_settings_handler.cc
diff --git a/chrome/browser/ui/webui/extensions/extension_settings_handler.cc b/chrome/browser/ui/webui/extensions/extension_settings_handler.cc
index f72083c638803e1930baf9ce496173c3529718ba..8885a5787721c52457bbf483e084b3168ae0ec37 100644
--- a/chrome/browser/ui/webui/extensions/extension_settings_handler.cc
+++ b/chrome/browser/ui/webui/extensions/extension_settings_handler.cc
@@ -211,6 +211,9 @@
     const Extension* extension,
     const std::vector<ExtensionPage>& pages,
     const ExtensionWarningService* warning_service) {
+  // The items which are to be written into app_dict are also described in
+  // chrome/browser/resources/extensions/extension_list.js in @typedef for
+  // ExtensionData. Please update it whenever you add or remove any keys here.
   base::DictionaryValue* extension_data = new base::DictionaryValue();
   bool enabled = extension_service_->IsExtensionEnabled(extension->id());
   GetExtensionBasicInfo(extension, enabled, extension_data);
@@ -815,6 +818,10 @@
 
 void ExtensionSettingsHandler::HandleRequestExtensionsData(
     const base::ListValue* args) {
+  // The items which are to be written into results are also described in
+  // chrome/browser/resources/extensions/extensions.js in @typedef for
+  // ExtensionDataResponse. Please update it whenever you add or remove any keys
+  // here.
   base::DictionaryValue results;
 
   Profile* profile = Profile::FromWebUI(web_ui());