views: use darker stroke for non-prominent buttons

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 246 matching lines @@
     kColorId_ButtonDisabledColor,
     kColorId_ButtonHoverColor,
     kColorId_ButtonPressedShade,
     kColorId_BlueButtonEnabledColor,
     kColorId_BlueButtonDisabledColor,
     kColorId_BlueButtonPressedColor,
     kColorId_BlueButtonHoverColor,
     kColorId_BlueButtonShadowColor,
     kColorId_ProminentButtonColor,
     kColorId_TextOnProminentButtonColor,
+    kColorId_ProminentButtonBorderColor,
+    kColorId_NonProminentButtonBorderColor,
     // MenuItem
     kColorId_EnabledMenuItemForegroundColor,
     kColorId_DisabledMenuItemForegroundColor,
     kColorId_SelectedMenuItemForegroundColor,
     kColorId_FocusedMenuItemBackgroundColor,
     kColorId_MenuSeparatorColor,
     kColorId_MenuBackgroundColor,
     kColorId_MenuBorderColor,
     // MenuButton - buttons in wrench menu
     kColorId_EnabledMenuButtonBorderColor,
@@ skipping 97 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_