[ozone/wayland] Fix fpermissive problem for GCC.

This fixes the following error:

wl::Object<wl_buffer> wl_buffer;
                      ^~~~~~~~~
In file included from ../../ui/ozone/platform/wayland/wayland_buffer_manager.h:18:0, from
 ../../ui/ozone/platform/wayland/wayland_buffer_manager.cc:5:
 ../../ui/ozone/platform/wayland/wayland_object.h:12:8: error: changes meaning
 of 'wl_buffer' from 'struct wl_buffer' [-fpermissive]  struct wl_buffer;
     ^~~~~~~~~

TBR=rjkroege@chromium.org

Change-Id: I326abd95fec4d26a4d0497e5570ae4e9f0637afb
Reviewed-on: https://chromium-review.googlesource.com/1213179
Commit-Queue: Maksim Sisov <msisov@igalia.com>
Reviewed-by: Maksim Sisov <msisov@igalia.com>
Cr-Commit-Position: refs/heads/master@{#589841}

ui/ozone/platform/wayland/wayland_buffer_manager.h

@@ -107,7 +107,7 @@ class WaylandBufferManager {
     zwp_linux_buffer_params_v1* params = nullptr;
 
     // A wl_buffer backed by a dmabuf created on the GPU side.
-    wl::Object<wl_buffer> wl_buffer;
+    wl::Object<struct wl_buffer> wl_buffer;
 
     // A callback, which is called once the |wl_frame_callback| from the server
     // is received.
@@ -120,7 +120,7 @@ class WaylandBufferManager {
 
     // A presentation feedback provided by the Wayland server once frame is
     // shown.
-    wl::Object<wp_presentation_feedback> wp_presentation_feedback;
+    wl::Object<struct wp_presentation_feedback> wp_presentation_feedback;
 
     DISALLOW_COPY_AND_ASSIGN(Buffer);
   };