Gtk3: Fix DCHECK on 3.20

chrome/browser/ui/libgtkui/gtk_util.cc

 // 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.
 
 #include "chrome/browser/ui/libgtkui/gtk_util.h"
 
 #include <dlfcn.h>
 #include <gdk/gdk.h>
 #include <gdk/gdkx.h>
 #include <gtk/gtk.h>
@@ skipping 512 matching lines @@
     return GetBgColorFromStyleContext(context);
   // This is verbatim how Gtk gets the selection color on versions before 3.20.
   GdkRGBA selection_color;
   G_GNUC_BEGIN_IGNORE_DEPRECATIONS;
   gtk_style_context_get_background_color(
       context, gtk_style_context_get_state(context), &selection_color);
   G_GNUC_END_IGNORE_DEPRECATIONS;
   return GdkRgbaToSkColor(selection_color);
 }
 
+bool ContextHasClass(GtkStyleContext* context, const std::string& style_class) {
+  return gtk_style_context_has_class(context, style_class.c_str()) ||
+         gtk_widget_path_iter_has_class(gtk_style_context_get_path(context), -1,
+                                        style_class.c_str());
+}
+
 SkColor GetSeparatorColor(const std::string& css_selector) {
   if (!GtkVersionCheck(3, 20))
     return GetFgColor(css_selector);
 
   auto context = GetStyleContextFromCss(css_selector);
   int w = 1, h = 1;
   gtk_style_context_get(context, gtk_style_context_get_state(context),
                         "min-width", &w, "min-height", &h, nullptr);
   GtkBorder border, padding;
   GtkStateFlags state = gtk_style_context_get_state(context);
   gtk_style_context_get_border(context, state, &border);
   gtk_style_context_get_padding(context, state, &padding);
   w += border.left + padding.left + padding.right + border.right;
   h += border.top + padding.top + padding.bottom + border.bottom;
 
-  bool horizontal = gtk_style_context_has_class(context, "horizontal");
+  bool horizontal = ContextHasClass(context, "horizontal");
   if (horizontal) {
     w = 24;
     h = std::max(h, 1);
   } else {
-    DCHECK(gtk_style_context_has_class(context, "vertical"));
+    DCHECK(ContextHasClass(context, "vertical"));
     h = 24;
     w = std::max(w, 1);
   }
 
   CairoSurface surface(gfx::Size(w, h));
   gtk_render_background(context, surface.cairo(), 0, 0, w, h);
   gtk_render_frame(context, surface.cairo(), 0, 0, w, h);
   return surface.GetAveragePixelValue(false);
 }
 #endif
 
 }  // namespace libgtkui