[ozone/wayland] Initialize zaura_shell on both shell_v6 and shell_stable

This is a follow up of https://crrev.com/c/2353116
([ozone/wayland] zaura_shell initial support).

BUG=1113900
R=msisov@chromium.org

Change-Id: I547f66e49e8ae4161ed15a7359f91b8b7ea17019
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2381253Reviewed-by: Maksim Sisov (GMT+3) <msisov@igalia.com>
Commit-Queue: Antonio Gomes (GMT-4) <tonikitoo@igalia.com>
Cr-Commit-Position: refs/heads/master@{#802633}

ui/ozone/platform/wayland/host/xdg_surface_wrapper_impl.cc

@@ -288,6 +288,9 @@ bool XDGSurfaceWrapperImpl::InitializeStable(bool with_toplevel) {
     return false;
   }
   xdg_toplevel_add_listener(xdg_toplevel_.get(), &xdg_toplevel_listener, this);
+
+  InitializeAuraShell();
+
   wayland_window_->root_surface()->Commit();
   connection_->ScheduleFlush();
   return true;
@@ -329,16 +332,21 @@ bool XDGSurfaceWrapperImpl::InitializeV6(bool with_toplevel) {
   zxdg_toplevel_v6_add_listener(zxdg_toplevel_v6_.get(),
                                 &zxdg_toplevel_v6_listener, this);
 
+  InitializeAuraShell();
+
+  wayland_window_->root_surface()->Commit();
+  connection_->ScheduleFlush();
+  return true;
+}
+
+void XDGSurfaceWrapperImpl::InitializeAuraShell() {
   if (connection_->aura_shell()) {
+    DCHECK(!aura_surface_);
     aura_surface_.reset(zaura_shell_get_aura_surface(
         connection_->aura_shell(), wayland_window_->root_surface()->surface()));
     zaura_surface_set_fullscreen_mode(aura_surface_.get(),
                                       ZAURA_SURFACE_FULLSCREEN_MODE_IMMERSIVE);
   }
-
-  wayland_window_->root_surface()->Commit();
-  connection_->ScheduleFlush();
-  return true;
 }
 
 }  // namespace ui

ui/ozone/platform/wayland/host/xdg_surface_wrapper_impl.h

@@ -77,6 +77,9 @@ class XDGSurfaceWrapperImpl : public ShellSurfaceWrapper {
   // Initializes using XDG Shell V6 protocol.
   bool InitializeV6(bool with_toplevel);
 
+  // Initializes the aura-shell EXO extension, if available.
+  void InitializeAuraShell();
+
   // Non-owing WaylandWindow that uses this surface wrapper.
   WaylandWindow* const wayland_window_;
   WaylandConnection* const connection_;