EXO: Refactored xdg_shell interface

Move xdg_shell interface  out of server.cc
This CL only moves code around.

Bug: 896710
Test: Built on ChromeOS
Change-Id: Idb117f086ffa995661291772b122b261aa869794
Reviewed-on: https://chromium-review.googlesource.com/c/1323901
Commit-Queue: Shawn Gallea <sagallea@google.com>
Reviewed-by: Daniele Castagna <dcastagna@chromium.org>
Reviewed-by: Daniel Nicoara <dnicoara@chromium.org>
Cr-Commit-Position: refs/heads/master@{#608666}

components/exo/wayland/BUILD.gn

@@ -57,6 +57,8 @@ source_set("wayland") {
     "zwp_input_timestamps_manager.h",
     "zwp_text_input_manager.cc",
     "zwp_text_input_manager.h",
+    "zxdg_shell.cc",
+    "zxdg_shell.h",
   ]
 
   defines = [ "EXO_IMPLEMENTATION" ]

components/exo/wayland/zxdg_shell.h

+// Copyright 2018 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.
+
+#ifndef COMPONENTS_EXO_WAYLAND_ZXDG_SHELL_H_
+#define COMPONENTS_EXO_WAYLAND_ZXDG_SHELL_H_
+
+#include <stdint.h>
+
+struct wl_client;
+
+namespace exo {
+namespace wayland {
+
+void bind_xdg_shell_v6(wl_client* client,
+                       void* data,
+                       uint32_t version,
+                       uint32_t id);
+
+}  // namespace wayland
+}  // namespace exo
+
+#endif  // COMPONENTS_EXO_WAYLAND_ZXDG_SHELL_H_