Fix to build Chromium 62 with GTK2

fix.diff

diff --git a/chrome/browser/ui/libgtkui/gtk_ui.h.orig b/chrome/browser/ui/libgtkui/gtk_ui.h
index 3048cf8..767f07e 100644
--- a/chrome/browser/ui/libgtkui/gtk_ui.h.orig
+++ b/chrome/browser/ui/libgtkui/gtk_ui.h
@@ -17,6 +17,7 @@
 #include "ui/gfx/color_utils.h"
 #include "ui/views/linux_ui/linux_ui.h"
 #include "ui/views/window/frame_buttons.h"
+#include "nav_button_layout_manager.h"
 
 typedef struct _GParamSpec GParamSpec;
 typedef struct _GtkStyle GtkStyle;
@@ -25,7 +26,6 @@ typedef struct _GtkWidget GtkWidget;
 namespace libgtkui {
 class Gtk2KeyBindingsHandler;
 class DeviceScaleFactorObserver;
-class NavButtonLayoutManager;
 
 // Interface to GTK2 desktop features.
 //