[gnome-control-center] search: Use a HdyColumn

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 7679f29a7a7c11704a08b9862cf4929e197eddb3
Author: Adrien Plazas <kekun plazas laposte net>
Date:   Tue Sep 25 07:52:50 2018 +0200

    search: Use a HdyColumn
    
    This better adapts the panel's size to the window's size, allowing it to
    look good on both large and narrow windows.

 panels/search/cc-search-panel.ui | 33 +++++++--------------------------
 1 file changed, 7 insertions(+), 26 deletions(-)
---
diff --git a/panels/search/cc-search-panel.ui b/panels/search/cc-search-panel.ui
index 8965e8d29..a4c5e2766 100644
--- a/panels/search/cc-search-panel.ui
+++ b/panels/search/cc-search-panel.ui
@@ -9,38 +9,19 @@
       <object class="GtkScrolledWindow" id="search_vbox">
         <property name="visible">True</property>
         <property name="hscrollbar_policy">never</property>
-        <property name="min_content_height">450</property>
         <child>
-          <object class="GtkBox">
+          <object class="HdyColumn">
             <property name="visible">True</property>
-            <property name="can_focus">False</property>
-
-            <!-- Stub boxes to make the content cover 1/3 of the screen -->
-            <child>
-              <object class="GtkBox">
-                <property name="visible">True</property>
-                <property name="can_focus">False</property>
-                <property name="hexpand">True</property>
-              </object>
-            </child>
-
-            <child>
-              <object class="GtkBox">
-                <property name="visible">True</property>
-                <property name="can_focus">False</property>
-                <property name="hexpand">True</property>
-              </object>
-              <packing>
-                <property name="pack_type">end</property>
-              </packing>
-            </child>
-
-            <!-- Content -->
+            <property name="maximum_width">600</property>
+            <property name="linear_growth_width">400</property>
+            <property name="margin_top">32</property>
+            <property name="margin_bottom">32</property>
+            <property name="margin_start">12</property>
+            <property name="margin_end">12</property>
             <child>
               <object class="GtkBox">
                 <property name="visible">True</property>
                 <property name="orientation">vertical</property>
-                <property name="margin">32</property>
                 <property name="hexpand">True</property>
                 <child>
                   <object class="GtkFrame" id="search_frame">