Have Chrome draw top window border when using custom titlebar.

chrome/browser/themes/theme_properties.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 CHROME_BROWSER_THEMES_THEME_PROPERTIES_H_
 #define CHROME_BROWSER_THEMES_THEME_PROPERTIES_H_
 
 #include <set>
 #include <string>
 
@@ skipping 137 matching lines @@
     COLOR_TOOLBAR_BUTTON_STROKE_INACTIVE,
     GRADIENT_FRAME_INCOGNITO,
     GRADIENT_FRAME_INCOGNITO_INACTIVE,
     GRADIENT_TOOLBAR,
     GRADIENT_TOOLBAR_INACTIVE,
     GRADIENT_TOOLBAR_BUTTON,
     GRADIENT_TOOLBAR_BUTTON_INACTIVE,
     GRADIENT_TOOLBAR_BUTTON_PRESSED,
     GRADIENT_TOOLBAR_BUTTON_PRESSED_INACTIVE,
 #endif  // OS_MACOSX
+
+#if defined(OS_WIN)
+    // The color of the 1px border around the window on Windows 10.
+    COLOR_ACCENT_BORDER,
+#endif  // OS_WIN
   };
 
   // Used by the browser theme pack to parse alignments from something like
   // "top left" into a bitmask of Alignment.
   static int StringToAlignment(const std::string& alignment);
 
   // Used by the browser theme pack to parse alignments from something like
   // "no-repeat" into a Tiling value.
   static int StringToTiling(const std::string& tiling);
 
@@ skipping 11 matching lines @@
 
   // Returns the default color for the given color |id| COLOR_* enum value.
   // Returns gfx::kPlaceholderColor if |id| is invalid.
   static SkColor GetDefaultColor(int id, bool otr);
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(ThemeProperties);
 };
 
 #endif  // CHROME_BROWSER_THEMES_THEME_PROPERTIES_H_