Add generic PaletteDelegate code.

ash/test/test_shell_delegate.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 ASH_TEST_TEST_SHELL_DELEGATE_H_
 #define ASH_TEST_TEST_SHELL_DELEGATE_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 36 matching lines @@
   keyboard::KeyboardUI* CreateKeyboardUI() override;
   void OpenUrlFromArc(const GURL& url) override;
   app_list::AppListPresenter* GetAppListPresenter() override;
   ShelfDelegate* CreateShelfDelegate(ShelfModel* model) override;
   SystemTrayDelegate* CreateSystemTrayDelegate() override;
   UserWallpaperDelegate* CreateUserWallpaperDelegate() override;
   TestSessionStateDelegate* CreateSessionStateDelegate() override;
   AccessibilityDelegate* CreateAccessibilityDelegate() override;
   NewWindowDelegate* CreateNewWindowDelegate() override;
   MediaDelegate* CreateMediaDelegate() override;
+  std::unique_ptr<PaletteDelegate> CreatePaletteDelegate() override;
   std::unique_ptr<PointerWatcherDelegate> CreatePointerWatcherDelegate()
       override;
   ui::MenuModel* CreateContextMenu(WmShelf* wm_shelf,
                                    const ShelfItem* item) override;
   GPUSupport* CreateGPUSupport() override;
   base::string16 GetProductName() const override;
   gfx::Image GetDeprecatedAcceleratorImage() const override;
 
   int num_exit_requests() const { return num_exit_requests_; }
 
@@ skipping 15 matching lines @@
       app_list_presenter_delegate_factory_;
   std::unique_ptr<app_list::AppListPresenterImpl> app_list_presenter_;
 
   DISALLOW_COPY_AND_ASSIGN(TestShellDelegate);
 };
 
 }  // namespace test
 }  // namespace ash
 
 #endif  // ASH_TEST_TEST_SHELL_DELEGATE_H_