[metacity/wip/invisible-borders: 3/25] MetaFrameBorders: add invisible borders

[Alberts Muktupāvels <muktupavels src gnome org>]

commit d919ba735af47c56895a7eb5cae2daefdaa6fddf
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Sun Jan 18 16:22:36 2015 +0200

    MetaFrameBorders: add invisible borders
    
    This just adds the invisible border field and populates it with
    data but doesn't use it in any way.
    
    Based on mutter commit:
    https://git.gnome.org/browse/mutter/commit/?id=a1a2527c75ab0c135f89396ea036336fb67ac538

 src/core/frame.c     |    8 ++++----
 src/include/common.h |    5 +++++
 src/ui/theme.c       |   10 ++++++++++
 3 files changed, 19 insertions(+), 4 deletions(-)
---
diff --git a/src/core/frame.c b/src/core/frame.c
index cb9e2df..e29a69b 100644
--- a/src/core/frame.c
+++ b/src/core/frame.c
@@ -306,10 +306,10 @@ meta_frame_get_flags (MetaFrame *frame)
 void
 meta_frame_borders_clear (MetaFrameBorders *self)
 {
-  self->visible.top = 0;
-  self->visible.bottom = 0;
-  self->visible.left = 0;
-  self->visible.right = 0;
+  self->visible.top = self->invisible.top = self->total.top = 0;
+  self->visible.bottom = self->invisible.bottom = self->total.bottom = 0;
+  self->visible.left = self->invisible.left = self->total.left = 0;
+  self->visible.right = self->invisible.right = self->total.right = 0;
 }
 
 void
diff --git a/src/include/common.h b/src/include/common.h
index fdd1df1..65ea0f7 100644
--- a/src/include/common.h
+++ b/src/include/common.h
@@ -269,6 +269,11 @@ struct _MetaFrameBorders
    * and an outer portion that is invisible but responds to events.
    */
   GtkBorder visible;
+  GtkBorder invisible;
+
+  /* For convenience, we have a "total" border which is equal to the sum
+   * of the two borders above. */
+  GtkBorder total;
 };
 
 /* sets all dimensions to zero */
diff --git a/src/ui/theme.c b/src/ui/theme.c
index 9728558..670a746 100644
--- a/src/ui/theme.c
+++ b/src/ui/theme.c
@@ -433,6 +433,16 @@ meta_frame_layout_get_borders (const MetaFrameLayout *layout,
       meta_frame_borders_clear (borders);
       return;
     }
+
+  borders->invisible.left = layout->invisible_border.left;
+  borders->invisible.right = layout->invisible_border.right;
+  borders->invisible.bottom = layout->invisible_border.bottom;
+  borders->invisible.top = layout->invisible_border.top;
+
+  borders->total.left = borders->invisible.left + borders->visible.left;
+  borders->total.right = borders->invisible.right + borders->visible.right;
+  borders->total.bottom = borders->invisible.bottom + borders->visible.bottom;
+  borders->total.top = borders->invisible.top + borders->visible.top;
 }
 
 static MetaButtonType