[mutter] compositor: Add "locate_pointer" vmethod

[Carlos Garnacho <carlosg src gnome org>]

commit b4c78726cf1d58ad2f40b2abc64f41ff726d6fbb
Author: Olivier Fourdan <ofourdan redhat com>
Date:   Wed Feb 20 11:07:22 2019 +0100

    compositor: Add "locate_pointer" vmethod
    
    This method is invoked to locate the pointer on screen.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/453
    https://gitlab.gnome.org/GNOME/gnome-shell/issues/981
    https://gitlab.gnome.org/GNOME/gsettings-desktop-schemas/merge_requests/19
    https://gitlab.gnome.org/GNOME/gnome-settings-daemon/merge_requests/86

 src/compositor/compositor-private.h  |  2 ++
 src/compositor/compositor.c          |  6 ++++++
 src/compositor/meta-plugin-manager.c | 10 ++++++++++
 src/compositor/meta-plugin-manager.h |  2 ++
 src/meta/meta-plugin.h               | 10 ++++++++++
 5 files changed, 30 insertions(+)
---
diff --git a/src/compositor/compositor-private.h b/src/compositor/compositor-private.h
index b08746d24..2bd7d696b 100644
--- a/src/compositor/compositor-private.h
+++ b/src/compositor/compositor-private.h
@@ -71,4 +71,6 @@ MetaCloseDialog * meta_compositor_create_close_dialog (MetaCompositor *composito
 MetaInhibitShortcutsDialog * meta_compositor_create_inhibit_shortcuts_dialog (MetaCompositor *compositor,
                                                                               MetaWindow     *window);
 
+void meta_compositor_locate_pointer (MetaCompositor *compositor);
+
 #endif /* META_COMPOSITOR_PRIVATE_H */
diff --git a/src/compositor/compositor.c b/src/compositor/compositor.c
index c8153cb3d..e4ffd1e84 100644
--- a/src/compositor/compositor.c
+++ b/src/compositor/compositor.c
@@ -1553,3 +1553,9 @@ meta_compositor_create_inhibit_shortcuts_dialog (MetaCompositor *compositor,
   return meta_plugin_manager_create_inhibit_shortcuts_dialog (compositor->plugin_mgr,
                                                               window);
 }
+
+void
+meta_compositor_locate_pointer (MetaCompositor *compositor)
+{
+  meta_plugin_manager_locate_pointer (compositor->plugin_mgr);
+}
diff --git a/src/compositor/meta-plugin-manager.c b/src/compositor/meta-plugin-manager.c
index ab2d8128f..45fba18da 100644
--- a/src/compositor/meta-plugin-manager.c
+++ b/src/compositor/meta-plugin-manager.c
@@ -405,3 +405,13 @@ meta_plugin_manager_create_inhibit_shortcuts_dialog (MetaPluginManager *plugin_m
 
   return meta_inhibit_shortcuts_dialog_default_new (window);
 }
+
+void
+meta_plugin_manager_locate_pointer (MetaPluginManager *plugin_mgr)
+{
+  MetaPlugin *plugin = plugin_mgr->plugin;
+  MetaPluginClass *klass = META_PLUGIN_GET_CLASS (plugin);
+
+  if (klass->locate_pointer)
+    klass->locate_pointer (plugin);
+}
diff --git a/src/compositor/meta-plugin-manager.h b/src/compositor/meta-plugin-manager.h
index 81ccdc01a..d1c007fa1 100644
--- a/src/compositor/meta-plugin-manager.h
+++ b/src/compositor/meta-plugin-manager.h
@@ -100,4 +100,6 @@ MetaInhibitShortcutsDialog *
   meta_plugin_manager_create_inhibit_shortcuts_dialog (MetaPluginManager *plugin_mgr,
                                                        MetaWindow        *window);
 
+void meta_plugin_manager_locate_pointer (MetaPluginManager *mgr);
+
 #endif
diff --git a/src/meta/meta-plugin.h b/src/meta/meta-plugin.h
index 6665531bf..b28836e88 100644
--- a/src/meta/meta-plugin.h
+++ b/src/meta/meta-plugin.h
@@ -239,6 +239,16 @@ struct _MetaPluginClass
    */
   MetaInhibitShortcutsDialog * (* create_inhibit_shortcuts_dialog) (MetaPlugin *plugin,
                                                                     MetaWindow *window);
+
+  /**
+   * MetaPluginClass::locate_pointer:
+   *
+   * Virtual function called when the user triggered the "locate-pointer"
+   * mechanism.
+   * The common way to implement this function is to show some animation
+   * on screen to draw user attention on the pointer location.
+   */
+  void (*locate_pointer) (MetaPlugin      *plugin);
 };
 
 /**