Mac: Update zoom bubble UI

ui/native_theme/native_theme_mac.h

+// Copyright (c) 2013 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 UI_NATIVE_THEME_NATIVE_THEME_MAC_H_
+#define UI_NATIVE_THEME_NATIVE_THEME_MAC_H_
+
+#include "ui/native_theme/native_theme_base.h"
+
+namespace ui {
+
+// Mac implementation of native theme support.
+class NativeThemeMac : public NativeThemeBase {
+ public:
+  static NativeThemeMac* instance();
+
+  virtual SkColor GetSystemColor(ColorId color_id) const OVERRIDE;
+
+ private:
+  NativeThemeMac();
+  virtual ~NativeThemeMac();
+
+  DISALLOW_COPY_AND_ASSIGN(NativeThemeMac);
+};
+
+}  // namespace ui
+
+#endif  // UI_NATIVE_THEME_NATIVE_THEME_MAC_H_