Add generic PaletteDelegate code.

chrome/browser/ui/ash/palette_delegate_chromeos.h

+// Copyright 2015 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_UI_ASH_PALETTE_DELEGATE_CHROMEOS_H_
+#define CHROME_BROWSER_UI_ASH_PALETTE_DELEGATE_CHROMEOS_H_
+
+#include <string>
+
+#include "ash/common/palette_delegate.h"
+#include "base/compiler_specific.h"
+#include "base/macros.h"
+#include "base/values.h"
+
+namespace chromeos {
+
+// A class which allows the Ash palette to perform chrome actions.
+class PaletteDelegateChromeOS : public ash::PaletteDelegate {
+ public:
+  PaletteDelegateChromeOS();
+  ~PaletteDelegateChromeOS() override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(PaletteDelegateChromeOS);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_UI_ASH_PALETTE_DELEGATE_CHROMEOS_H_