[tabbed options] tidy up some bits of content settings

chrome/browser/resources/shared/js/cr.js

 // Copyright (c) 2010 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.
 
 const cr = (function() {
 
   /**
    * Whether we are using a Mac or not.
    * @type {boolean}
    */
   const isMac = /Mac/.test(navigator.platform);
 
   /**
    * Whether this is on the Windows platform or not.
    * @type {boolean}
    */
   const isWindows = /Win/.test(navigator.platform);
 
   /**
    * Whether this is on chromeOS or not.
    * @type {boolean}
    */
   const isChromeOS = /CrOS/.test(navigator.userAgent);
 
   /**
+   * Whether this is on vanilla Linux (not chromeOS).
+   * @type {boolean}
+   */
+  const isLinux = /Linux/.test(navigator.userAgent);
+
+  /**
    * Whether this uses the views toolkit or not.
    * @type {boolean}
    */
   const isViews = isWindows || isChromeOS;
 
   /**
    * Builds an object structure for the provided namespace path,
    * ensuring that names that already exist are not overwritten. For
    * example:
    * "a.b.c" -> a = {};a.b={};a.b.c={};
@@ skipping 282 matching lines @@
     ctor.getInstance = function() {
       return ctor.instance_ || (ctor.instance_ = new ctor());
     };
   }
 
   return {
     addSingletonGetter: addSingletonGetter,
     isChromeOS: isChromeOS,
     isMac: isMac,
     isWindows: isWindows,
+    isLinux: isLinux,
+    isViews: isViews,
     define: define,
     defineProperty: defineProperty,
     PropertyKind: PropertyKind,
     createUid: createUid,
     getUid: getUid,
     dispatchSimpleEvent: dispatchSimpleEvent,
     dispatchPropertyChange: dispatchPropertyChange,
 
     /**
      * The document that we are currently using.
      * @type {!Document}
      */
     get doc() {
       return doc;
     },
     withDoc: withDoc,
     Event: CrEvent
   };
 })();