GTK: Even more cleanup to access allocation through the accessor.

chrome/browser/ui/gtk/tabs/tab_renderer_gtk.cc

Index: chrome/browser/ui/gtk/tabs/tab_renderer_gtk.cc
diff --git a/chrome/browser/ui/gtk/tabs/tab_renderer_gtk.cc b/chrome/browser/ui/gtk/tabs/tab_renderer_gtk.cc
index 7b9aff92fb6305d550ff4f2ceb7d311f2248000d..d419dd54cfe1278590562d0b6a16c48b63424553 100644
--- a/chrome/browser/ui/gtk/tabs/tab_renderer_gtk.cc
+++ b/chrome/browser/ui/gtk/tabs/tab_renderer_gtk.cc
@@ -99,9 +99,13 @@ gfx::Rect GetWidgetBoundsRelativeToParent(GtkWidget* parent,
                                           GtkWidget* widget) {
   gfx::Point parent_pos = gtk_util::GetWidgetScreenPosition(parent);
   gfx::Point widget_pos = gtk_util::GetWidgetScreenPosition(widget);
+
+  GtkAllocation allocation;
+  gtk_widget_get_allocation(widget, &allocation);
+
   return gfx::Rect(widget_pos.x() - parent_pos.x(),
                    widget_pos.y() - parent_pos.y(),
-                   widget->allocation.width, widget->allocation.height);
+                   allocation.width, allocation.height);
 }
 
 }  // namespace