Add generic PaletteDelegate code.

ash/common/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_COMMON_SHELL_DELEGATE_H_
 #define ASH_COMMON_SHELL_DELEGATE_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 23 matching lines @@
 namespace views {
 class Widget;
 }
 
 namespace ash {
 
 class AccessibilityDelegate;
 class GPUSupport;
 class MediaDelegate;
 class NewWindowDelegate;
+class PaletteDelegate;
 class PointerWatcherDelegate;
 class SessionStateDelegate;
 class ShelfDelegate;
 class ShelfModel;
 class SystemTrayDelegate;
 class UserWallpaperDelegate;
 struct ShelfItem;
 class WmShelf;
 class WmWindow;
 
@@ skipping 62 matching lines @@
 
   // Creates a accessibility delegate. Shell takes ownership of the delegate.
   virtual AccessibilityDelegate* CreateAccessibilityDelegate() = 0;
 
   // Creates an application delegate. Shell takes ownership of the delegate.
   virtual NewWindowDelegate* CreateNewWindowDelegate() = 0;
 
   // Creates a media delegate. Shell takes ownership of the delegate.
   virtual MediaDelegate* CreateMediaDelegate() = 0;
 
+  // Creates a palette delegate. Shell takes ownership of the delegate.
+  virtual PaletteDelegate* CreatePaletteDelegate() = 0;

[Daniel Erat, 2016/08/02 21:35:01]

how about returning std::unique_ptr<PaletteDelegate> so the ownership transfer
is clear? note that the next method already does this.

[jdufault, 2016/08/04 23:55:29]

Done.

+
   virtual std::unique_ptr<PointerWatcherDelegate>
   CreatePointerWatcherDelegate() = 0;
 
   // Creates a menu model for the |wm_shelf| and optional shelf |item|.
   // If |item| is null, this creates a context menu for the desktop or shelf.
   virtual ui::MenuModel* CreateContextMenu(WmShelf* wm_shelf,
                                            const ShelfItem* item) = 0;
 
   // Creates a GPU support object. Shell takes ownership of the object.
   virtual GPUSupport* CreateGPUSupport() = 0;
 
   // Get the product name.
   virtual base::string16 GetProductName() const = 0;
 
   virtual void OpenKeyboardShortcutHelpPage() const {}
 
   virtual gfx::Image GetDeprecatedAcceleratorImage() const = 0;
 
   // Toggles the status of the touchpad / touchscreen on or off.
   virtual void ToggleTouchpad() {}
   virtual void ToggleTouchscreen() {}
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SHELL_DELEGATE_H_