extensions: clean up hiding/showing of developer controls.

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 a62d206aee7cdecef398f8c61674f8f13d69d5c1..210867de012130b6bcbab9f3e072649490155074 100644
--- a/chrome/browser/ui/webui/extensions/extension_settings_handler.cc
+++ b/chrome/browser/ui/webui/extensions/extension_settings_handler.cc
@@ -990,10 +990,10 @@ void ExtensionSettingsHandler::HandleToggleDeveloperMode(
   if (profile->IsSupervised())
     return;
 
-  bool developer_mode =
-      !profile->GetPrefs()->GetBoolean(prefs::kExtensionsUIDeveloperMode);
+  bool developer_mode_on;
+  CHECK(args->GetBoolean(0, &developer_mode_on));
   profile->GetPrefs()->SetBoolean(prefs::kExtensionsUIDeveloperMode,
-                                  developer_mode);
+                                  developer_mode_on);
 }
 
 void ExtensionSettingsHandler::HandleInspectMessage(