Add support for drawing window caption buttons on windows.

ui/native_theme/native_theme.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 UI_NATIVE_THEME_NATIVE_THEME_H_
 #define UI_NATIVE_THEME_NATIVE_THEME_H_
 
 #include "base/macros.h"
 #include "base/observer_list.h"
 #include "build/build_config.h"
@@ skipping 66 matching lines @@
     // The corner is drawn when there is both a horizontal and vertical
     // scrollbar.
     kScrollbarCorner,
     kSliderTrack,
     kSliderThumb,
     kTabPanelBackground,
     kTextField,
     kTrackbarThumb,
     kTrackbarTrack,
     kWindowResizeGripper,
+
+    // Parts used in the title bar of the window.
+    kCaptionMin,
+    kCaptionMax,
+    kCaptionRestore,
+    kCaptionClose,
+
     kMaxPart,
   };
 
   // The state of the part.
   enum State {
     // IDs defined as specific values for use in arrays.
     kDisabled = 0,
     kHovered  = 1,
     kNormal   = 2,
     kPressed  = 3,
@@ skipping 282 matching lines @@
  private:
   // Observers to notify when the native theme changes.
   base::ObserverList<NativeThemeObserver> native_theme_observers_;
 
   DISALLOW_COPY_AND_ASSIGN(NativeTheme);
 };
 
 }  // namespace ui
 
 #endif  // UI_NATIVE_THEME_NATIVE_THEME_H_