Fix painting of scaled themes in Windows in high-DPI mode.

ui/native_theme/native_theme_win.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_WIN_H_
 #define UI_NATIVE_THEME_NATIVE_THEME_WIN_H_
 
 // A wrapper class for working with custom XP/Vista themes provided in
 // uxtheme.dll.  This is a singleton class that can be grabbed using
 // NativeThemeWin::instance().
@@ skipping 239 matching lines @@
   HRESULT PaintWindowResizeGripper(HDC hdc, const gfx::Rect& rect) const;
 
   HRESULT PaintTabPanelBackground(HDC hdc, const gfx::Rect& rect) const;
 
   HRESULT PaintTextField(HDC hdc,
                          Part part,
                          State state,
                          const gfx::Rect& rect,
                          const TextFieldExtraParams& extra) const;
 
+  // Paints a theme part, with support for scene scaling in high-DPI mode.
+  // |theme| is the theme handle. |hdc| is the handle for the device context.
+  // |part_id| is the identifier for the part (e.g. thumb gripper). |state_id|
+  // is the identifier for the rendering state of the part (e.g. hover). |rect|
+  // is the bounds for rendering, expressed in logical coordinates.
+  HRESULT PaintScaledTheme(HANDLE theme,
+                           HDC hdc,
+                           int part_id,
+                           int state_id,
+                           const gfx::Rect& rect) const;
 
   // Get the windows theme name/part/state.  These three helper functions are
   // used only by GetPartSize(), as each of the corresponding PaintXXX()
   // methods do further validation of the part and state that is required for
   // getting the size.
   static ThemeName GetThemeName(Part part);
   static int GetWindowsPart(Part part, State state, const ExtraParams& extra);
   static int GetWindowsState(Part part, State state, const ExtraParams& extra);
 
   HRESULT GetThemeInt(ThemeName theme,
@@ skipping 75 matching lines @@
   // The system color change listener and the updated cache of system colors.
   gfx::ScopedSysColorChangeListener color_change_listener_;
   mutable std::map<int, SkColor> system_colors_;
 
   DISALLOW_COPY_AND_ASSIGN(NativeThemeWin);
 };
 
 }  // namespace ui
 
 #endif  // UI_NATIVE_THEME_NATIVE_THEME_WIN_H_