Make SysColorChangeListener Windows-only instead of having an empty shell.

ui/gfx/color_utils.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_GFX_COLOR_UTILS_H_
 #define UI_GFX_COLOR_UTILS_H_
 
 #include "base/basictypes.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/gfx/gfx_export.h"
@@ skipping 85 matching lines @@
 // NOTE: This won't do anything but waste time if the supplied foreground color
 // has a luma value close to the midpoint (0.5 in the HSL representation).
 GFX_EXPORT SkColor GetReadableColor(SkColor foreground, SkColor background);
 
 // Invert a color.
 GFX_EXPORT SkColor InvertColor(SkColor color);
 
 // Gets a Windows system color as a SkColor
 GFX_EXPORT SkColor GetSysSkColor(int which);
 
+// Returns true only if Chrome should use an inverted color scheme - which is
+// only true if the system has high-contrast mode enabled and and is using a
+// light-on-dark color scheme.
+GFX_EXPORT bool IsInvertedColorScheme();
+
 }  // namespace color_utils
 
 #endif  // UI_GFX_COLOR_UTILS_H_