Gtk3: Fix separator color on Gtk3.20

chrome/browser/ui/libgtkui/native_theme_gtk3.cc

Index: chrome/browser/ui/libgtkui/native_theme_gtk3.cc
diff --git a/chrome/browser/ui/libgtkui/native_theme_gtk3.cc b/chrome/browser/ui/libgtkui/native_theme_gtk3.cc
index 6be1acba24f118af6a8b532f3fd978c7c21e601f..9b2254946d84451d3f4ef7f37bd7189696b1bc74 100644
--- a/chrome/browser/ui/libgtkui/native_theme_gtk3.cc
+++ b/chrome/browser/ui/libgtkui/native_theme_gtk3.cc
@@ -101,7 +101,10 @@ SkColor SkColorFromColorId(ui::NativeTheme::ColorId color_id) {
     case ui::NativeTheme::kColorId_EnabledMenuButtonBorderColor:
     case ui::NativeTheme::kColorId_FocusedMenuButtonBorderColor:
     case ui::NativeTheme::kColorId_HoverMenuButtonBorderColor:
-      return GetFgColor("GtkMenu#menu GtkMenuItem#menuitem.separator:disabled");
+      if (GtkVersionCheck(3, 20))
+        return GetBgColor("GtkMenu#menu GtkSeparator#separator");
+      else
+        return GetFgColor("GtkMenu#menu GtkMenuItem#menuitem.separator");
 
     // Label
     case ui::NativeTheme::kColorId_LabelEnabledColor:
@@ -137,7 +140,10 @@ SkColor SkColorFromColorId(ui::NativeTheme::ColorId color_id) {
 
     // Separator
     case ui::NativeTheme::kColorId_SeparatorColor:
-      return GetFgColor("GtkSeparator#separator.horizontal");
+      if (GtkVersionCheck(3, 20))
+        return GetBgColor("GtkSeparator#separator.horizontal");
+      else
+        return GetFgColor("GtkSeparator#separator.horizontal");
 
     // Button
     case ui::NativeTheme::kColorId_ButtonEnabledColor: