Tabs API is usable without tabs permission.

chrome/browser/extensions/window_controller.h

 // Copyright (c) 2012 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.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_WINDOW_CONTROLLER_H_
 #define CHROME_BROWSER_EXTENSIONS_WINDOW_CONTROLLER_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 39 matching lines @@
 
   // Return the type name for the window.
   virtual std::string GetWindowTypeText() const = 0;
 
   // Populates a dictionary for the Window object. Override this to set
   // implementation specific properties (call the base implementation first to
   // set common properties).
   virtual base::DictionaryValue* CreateWindowValue() const;
 
   // Populates a dictionary for the Window object, including a list of tabs.
-  virtual base::DictionaryValue* CreateWindowValueWithTabs() const = 0;
+  virtual base::DictionaryValue* CreateWindowValueWithTabs(
+      const extensions::Extension* extension) const = 0;
 
   // Returns false if the window is in a state where closing the window is not
   // permitted and sets |reason| if not NULL.
   virtual bool CanClose(Reason* reason) const = 0;
 
   // Set the window's fullscreen state. |extension_url| provides the url
   // associated with the extension (used by FullscreenController).
   virtual void SetFullscreenMode(bool is_fullscreen,
                                  const GURL& extension_url) const = 0;
 
   // Returns a Browser if available. Defaults to returning NULL.
   // TODO(stevenjb): Temporary workaround. Eliminate this.
   virtual Browser* GetBrowser() const;
 
   // Extension/window visibility and ownership is window-specific, subclasses
   // need to define this behavior.
   virtual bool IsVisibleToExtension(const Extension* extension) const = 0;
 
  private:
   BaseWindow* window_;
   Profile* profile_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowController);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_WINDOW_CONTROLLER_H_