[gnome-control-center/wip/jsparber/background: 11/28] background: add white space around gallery and min/max per line

[Julian Sparber <jsparber src gnome org>]

commit 4c04af99450d7a0cfd615107cf7d27b9cb1cd52d
Author: Julian Sparber <julian sparber net>
Date:   Mon Nov 13 20:12:04 2017 +0100

    background: add white space around gallery and min/max per line
    
    - set min thumbnails per line to 5
    - set max thumbnails per line to 5
    
    https://bugzilla.gnome.org/show_bug.cgi?id=788515

 panels/background/background.ui                  | 118 +++--
 panels/background/cc-background-chooser-dialog.c | 616 -----------------------
 panels/background/cc-background-chooser-dialog.h |  38 --
 panels/background/test-chooser-dialog.c          |  37 --
 4 files changed, 63 insertions(+), 746 deletions(-)
---
diff --git a/panels/background/background.ui b/panels/background/background.ui
index 083fbf92c..d188dd449 100644
--- a/panels/background/background.ui
+++ b/panels/background/background.ui
@@ -5,13 +5,6 @@
     <property name="visible">True</property>
     <property name="can_focus">False</property>
     <property name="hexpand">True</property>
-    <child>
-      <object class="GtkBox" id="left_space">
-        <property name="visible">True</property>
-        <property name="can_focus">False</property>
-        <property name="expand">True</property>
-      </object>
-    </child>
     <child>
       <object class="GtkBox" id="content">
         <property name="visible">True</property>
@@ -142,61 +135,54 @@
                 <property name="can_focus">False</property>
                 <property name="hscrollbar_policy">never</property>
                 <child>
-                  <object class="GtkBox" id="box4">
+                  <object class="GtkBox">
                     <property name="visible">True</property>
                     <property name="can_focus">False</property>
-                    <property name="orientation">vertical</property>
+                    <property name="expand">True</property>
                     <child>
-                      <object class="GtkFlowBox" id="background-gallery">
+                      <object class="GtkBox" id="left_space">
                         <property name="visible">True</property>
                         <property name="can_focus">False</property>
-                        <property name="hexpand">True</property>
-                        <property name="vexpand">False</property>
-                        <property name="homogeneous">True</property>
-                        <property name="orientation">horizontal</property>
-                        <property name="min-children-per-line">2</property>
-                        <property name="max-children-per-line">1000</property>
-                        <property name="row_spacing">5</property>
-                        <property name="column_spacing">5</property>
-                        <property name="halign">fill</property>
-                        <property name="valign">fill</property>
-                        <property name="margin">25</property>
+                        <property name="expand">True</property>
                       </object>
                     </child>
                     <child>
-                      <object class="GtkBox">
+                      <object class="GtkBox" id="box4">
                         <property name="visible">True</property>
                         <property name="can_focus">False</property>
-                        <property name="halign">center</property>
-                        <property name="valign">end</property>
-                        <property name="margin">32</property>
-                        <property name="margin_top">7</property>
                         <property name="orientation">vertical</property>
-                        <property name="spacing">16</property>
                         <child>
-                          <object class="GtkLabel">
+                          <object class="GtkFlowBox" id="background-gallery">
                             <property name="visible">True</property>
                             <property name="can_focus">False</property>
-                            <property name="label" translatable="yes">Photos or Files can be used to set any 
image as the background</property>
+                            <property name="hexpand">True</property>
+                            <property name="vexpand">False</property>
+                            <property name="homogeneous">True</property>
+                            <property name="orientation">horizontal</property>
+                            <property name="min-children-per-line">2</property>
+                            <property name="max-children-per-line">5</property>
+                            <property name="row_spacing">5</property>
+                            <property name="column_spacing">5</property>
+                            <property name="halign">fill</property>
+                            <property name="valign">fill</property>
+                            <property name="margin">25</property>
                           </object>
-                          <packing>
-                            <property name="expand">False</property>
-                            <property name="fill">True</property>
-                            <property name="position">0</property>
-                          </packing>
                         </child>
                         <child>
                           <object class="GtkBox">
                             <property name="visible">True</property>
                             <property name="can_focus">False</property>
                             <property name="halign">center</property>
+                            <property name="valign">end</property>
+                            <property name="margin">32</property>
+                            <property name="margin_top">7</property>
+                            <property name="orientation">vertical</property>
                             <property name="spacing">16</property>
                             <child>
-                              <object class="GtkButton" id="open-gnome-photos">
-                                <property name="label" translatable="yes">Open Photos app</property>
+                              <object class="GtkLabel">
                                 <property name="visible">True</property>
-                                <property name="can_focus">True</property>
-                                <property name="receives_default">True</property>
+                                <property name="can_focus">False</property>
+                                <property name="label" translatable="yes">Photos or Files can be used to set 
any image as the background</property>
                               </object>
                               <packing>
                                 <property name="expand">False</property>
@@ -205,11 +191,37 @@
                               </packing>
                             </child>
                             <child>
-                              <object class="GtkButton" id="open-picture-folder">
-                                <property name="label" translatable="yes">Open Pictures folder</property>
+                              <object class="GtkBox">
                                 <property name="visible">True</property>
-                                <property name="can_focus">True</property>
-                                <property name="receives_default">True</property>
+                                <property name="can_focus">False</property>
+                                <property name="halign">center</property>
+                                <property name="spacing">16</property>
+                                <child>
+                                  <object class="GtkButton" id="open-gnome-photos">
+                                    <property name="label" translatable="yes">Open Photos app</property>
+                                    <property name="visible">True</property>
+                                    <property name="can_focus">True</property>
+                                    <property name="receives_default">True</property>
+                                  </object>
+                                  <packing>
+                                    <property name="expand">False</property>
+                                    <property name="fill">True</property>
+                                    <property name="position">0</property>
+                                  </packing>
+                                </child>
+                                <child>
+                                  <object class="GtkButton" id="open-picture-folder">
+                                    <property name="label" translatable="yes">Open Pictures folder</property>
+                                    <property name="visible">True</property>
+                                    <property name="can_focus">True</property>
+                                    <property name="receives_default">True</property>
+                                  </object>
+                                  <packing>
+                                    <property name="expand">False</property>
+                                    <property name="fill">True</property>
+                                    <property name="position">1</property>
+                                  </packing>
+                                </child>
                               </object>
                               <packing>
                                 <property name="expand">False</property>
@@ -218,21 +230,24 @@
                               </packing>
                             </child>
                           </object>
-                          <packing>
-                            <property name="expand">False</property>
-                            <property name="fill">True</property>
-                            <property name="position">1</property>
-                          </packing>
                         </child>
                       </object>
                     </child>
+                    <child>
+                      <object class="GtkBox" id="right_space">
+                        <property name="visible">True</property>
+                        <property name="can_focus">False</property>
+                        <property name="expand">True</property>
+                      </object>
+
+                    </child>
                   </object>
                 </child>
               </object>
               <packing>
                 <property name="expand">True</property>
                 <property name="fill">True</property>
-                <property name="position">0</property>
+                <property name="position">1</property>
               </packing>
             </child>
           </object>
@@ -244,13 +259,6 @@
         </child>
       </object>
     </child>
-    <child>
-      <object class="GtkBox" id="right_space">
-        <property name="visible">True</property>
-        <property name="can_focus">False</property>
-        <property name="expand">True</property>
-      </object>
-    </child>
   </object>
   <object class="GtkListStore" id="sources-liststore">
     <columns>