DevTools: remove Object.observe usage, it is being deprecated.

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 72 matching lines @@
             try {
                 var settings = JSON.parse(window.decodeURI(settingsParam));
                 for (var key in settings)
                     prefs[key] = settings[key];
             } catch(e) {
                 // Ignore malformed settings.
             }
         }
 
         this._initializeExperiments(prefs);
-
-        /**
-         * @param {!Array<{name: string}>} changes
-         */
-        function trackPrefsObject(changes)
-        {
-            if (!Object.keys(prefs).length) {
-                InspectorFrontendHost.clearPreferences();
-                return;
-            }
-
-            for (var change of changes) {
-                var name = change.name;
-                if (name in prefs)
-                    InspectorFrontendHost.setPreference(name, prefs[name]);
-                else
-                    InspectorFrontendHost.removePreference(name);
-            }
-        }
-
-        Object.observe(prefs, trackPrefsObject);
-        WebInspector.settings = new WebInspector.Settings(prefs);
+        WebInspector.settings = new WebInspector.Settings(new WebInspector.SettingsStorage(prefs,
+            InspectorFrontendHost.setPreference, InspectorFrontendHost.removePreference, InspectorFrontendHost.clearPreferences));
 
         if (!InspectorFrontendHost.isUnderTest())
             new WebInspector.VersionController().updateVersion();
     },
 
     /**
      * @param {!Object<string, string>} prefs
      */
     _initializeExperiments: function(prefs)
     {
@@ skipping 959 matching lines @@
      */
     willHide: function()
     {
         this._hideCallback.call(null);
     },
 
     __proto__: WebInspector.VBox.prototype
 }
 
 new WebInspector.Main();