Pass button_rect when opening window menu from button

When opening the window menu without an associated control - e.g.
by right-clicking the titlebar or by keyboard - using coordinates
for the menu position is appropriate. However when the menu is
associated with a window button, the expected behavior in the
shell can be implemented much easier with the full button geometry:
the menu will point to the center of the button's bottom edge
rather than align to the left/right side of the titlebar as it
does now, and the clickable area where a release event does not
dismiss the menu will match the actual clickable area in mutter.

So add an additional show_window_menu_for_rect() function and
use it when opening the menu from a button.

https://bugzilla.gnome.org/show_bug.cgi?id=731058

src/core/core.c

@@ -392,6 +392,22 @@ meta_core_show_window_menu (Display            *xdisplay,
   meta_window_show_menu (window, menu, root_x, root_y);
 }
 
+void
+meta_core_show_window_menu_for_rect (Display            *xdisplay,
+                                     Window              frame_xwindow,
+                                     MetaWindowMenuType  menu,
+                                     MetaRectangle      *rect,
+                                     guint32             timestamp)
+{
+  MetaWindow *window = get_window (xdisplay, frame_xwindow);
+
+  if (meta_prefs_get_raise_on_click ())
+    meta_window_raise (window);
+  meta_window_focus (window, timestamp);
+
+  meta_window_show_menu_for_rect (window, menu, rect);
+}
+
 const char*
 meta_core_get_workspace_name_with_index (Display *xdisplay,
                                          Window   xroot,

src/core/core.h

@@ -26,6 +26,7 @@
 /* Don't include core headers here */
 #include <gdk/gdkx.h>
 #include <meta/common.h>
+#include <meta/boxes.h>
 
 typedef enum
 {
@@ -138,6 +139,12 @@ void meta_core_show_window_menu (Display            *xdisplay,
                                  int                 root_y,
                                  guint32             timestamp);
 
+void meta_core_show_window_menu_for_rect (Display            *xdisplay,
+                                          Window              frame_xwindow,
+                                          MetaWindowMenuType  menu,
+                                          MetaRectangle      *rect,
+                                          guint32             timestamp);
+
 gboolean   meta_core_begin_grab_op (Display    *xdisplay,
                                     Window      frame_xwindow,
                                     MetaGrabOp  op,

src/core/window-private.h

@@ -575,6 +575,10 @@ void meta_window_show_menu (MetaWindow         *window,
                             int                 x,
                             int                 y);
 
+void meta_window_show_menu_for_rect (MetaWindow         *window,
+                                     MetaWindowMenuType  menu,
+                                     MetaRectangle      *rect);
+
 gboolean meta_window_handle_mouse_grab_op_event  (MetaWindow         *window,
                                                   const ClutterEvent *event);
 

src/core/window.c

@@ -5251,6 +5251,15 @@ meta_window_show_menu (MetaWindow         *window,
   meta_compositor_show_window_menu (window->display->compositor, window, menu, x, y);
 }
 
+void
+meta_window_show_menu_for_rect (MetaWindow         *window,
+                                MetaWindowMenuType  menu,
+                                MetaRectangle      *rect)
+{
+  g_return_if_fail (!window->override_redirect);
+  meta_compositor_show_window_menu_for_rect (window->display->compositor, window, menu, rect);
+}
+
 void
 meta_window_shove_titlebar_onscreen (MetaWindow *window)
 {