DevTools: settings of custom devtools should not interfere with bundled devtools

third_party/WebKit/Source/devtools/front_end/main/Main.js

 /*
  * Copyright (C) 2006, 2007, 2008 Apple Inc.  All rights reserved.
  * Copyright (C) 2007 Matt Lilek (pewtermoose@gmail.com).
  * Copyright (C) 2009 Joseph Pecoraro
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
@@ skipping 55 matching lines @@
     this._createSettings(prefs);
     this._createAppUI();
   }
 
   /**
    * @param {!Object<string, string>} prefs
    * Note: this function is called from testSettings in Tests.js.
    */
   _createSettings(prefs) {
     this._initializeExperiments(prefs);
-    WebInspector.settings = new WebInspector.Settings(new WebInspector.SettingsStorage(
+    var storagePrefix = WebInspector.isCustomDevtoolsFrontend() ? '__custom__' : '';
+    var clearLocalStorage = window.localStorage ? window.localStorage.clear.bind(window.localStorage) : undefined;
+    var localStorage =
+        new WebInspector.SettingsStorage(window.localStorage || {}, undefined, undefined, clearLocalStorage, storagePrefix);
+    var globalStorage = new WebInspector.SettingsStorage(
         prefs, InspectorFrontendHost.setPreference, InspectorFrontendHost.removePreference,
-        InspectorFrontendHost.clearPreferences));
+        InspectorFrontendHost.clearPreferences, storagePrefix);
+    WebInspector.settings = new WebInspector.Settings(globalStorage, localStorage);
 
     if (!InspectorFrontendHost.isUnderTest())
       new WebInspector.VersionController().updateVersion();
   }
 
   /**
    * @param {!Object<string, string>} prefs
    */
   _initializeExperiments(prefs) {
     Runtime.experiments.register('accessibilityInspection', 'Accessibility Inspection');
@@ skipping 952 matching lines @@
    * @override
    * @return {?Element}
    */
   settingElement() {
     return WebInspector.SettingsUI.createSettingCheckbox(
         WebInspector.UIString('Show rulers'), WebInspector.moduleSetting('showMetricsRulers'));
   }
 };
 
 new WebInspector.Main();