[shotwell] Delay size_request in CheckerboardLayout

[Jens Georg <jensgeorg src gnome org>]

commit 4a70d87baeb993c015611f71af39bdc77893ae08
Author: Jens Georg <mail jensge org>
Date:   Sun May 29 22:01:11 2016 +0200

    Delay size_request in CheckerboardLayout
    
    If we do a size_request with height = 0, the size_request in do_reflow does
    not lead to a re-allocation.
    
    Signed-off-by: Jens Georg <mail jensge org>
    
    https://bugzilla.gnome.org/show_bug.cgi?id=766864

 src/CheckerboardLayout.vala |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)
---
diff --git a/src/CheckerboardLayout.vala b/src/CheckerboardLayout.vala
index 3221776..032235f 100644
--- a/src/CheckerboardLayout.vala
+++ b/src/CheckerboardLayout.vala
@@ -911,7 +911,11 @@ public class CheckerboardLayout : Gtk.DrawingArea {
             debug("on_viewport_resized: due_to_reflow=%s set_size_request %dx%d",
                 size_allocate_due_to_reflow.to_string(), parent_allocation.width, req.height);
 #endif
-            set_size_request(parent_allocation.width - SCROLLBAR_PLACEHOLDER_WIDTH, req.height);
+            // But if the current height is 0, don't request a size yet. Delay
+            // it to do_reflow (bgo#766864)
+            if (req.height != 0) {
+                set_size_request(parent_allocation.width - SCROLLBAR_PLACEHOLDER_WIDTH, req.height);
+            }
         } else {
             // set the layout's width and height to always match the parent's
             set_size_request(parent_allocation.width, parent_allocation.height);