Have Chrome draw top window border when using custom titlebar.

chrome/browser/themes/theme_properties.cc

 // 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.
 
 #include "chrome/browser/themes/theme_properties.h"
 
 #include <memory>
 
 #include "base/macros.h"
 #include "base/strings/string_split.h"
@@ skipping 335 matching lines @@
     case COLOR_TOOLBAR_STROKE:
       return otr ? kDefaultColorToolbarIncognitoStroke[mode]
                  : kDefaultColorToolbarStroke[mode];
     case COLOR_TOOLBAR_STROKE_INACTIVE:
       return kDefaultColorToolbarStrokeInactive;
     case COLOR_TOOLBAR_STROKE_THEME:
       return kDefaultColorToolbarStrokeTheme;
     case COLOR_TOOLBAR_STROKE_THEME_INACTIVE:
       return kDefaultColorToolbarStrokeThemeInactive;
 #endif
+#if defined(OS_WIN)
+    case COLOR_ACCENT_BORDER:
+      NOTREACHED();
+      return gfx::kPlaceholderColor;
+#endif
+
     case COLOR_FRAME_INCOGNITO:
     case COLOR_FRAME_INCOGNITO_INACTIVE:
       NOTREACHED() << "These values should be queried via their respective "
                       "non-incognito equivalents and an appropriate |otr| "
                       "value.";
-    default:
       return gfx::kPlaceholderColor;
   }
+
+  return gfx::kPlaceholderColor;
 }