[gnome-shell] extensionPrefs: Add info popover to headerbar

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

commit b47879d0a7871948a7dd290a5cd6c7c0b60f5d79
Author: Florian Müllner <fmuellner gnome org>
Date:   Fri Jan 24 19:00:37 2020 +0100

    extensionPrefs: Add info popover to headerbar
    
    Extensions can have a major impact on stability and performance. Now that
    the tool will become the main way for users to manage their extensions, it
    is an appropriate place to warn the user of that risk.
    
    Add a small info popover to the headerbar to display that warning, together
    with the previously removed hint of where to go for finding new extensions.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/issues/1968

 js/extensionPrefs/ui/extensions-window.ui | 50 +++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)
---
diff --git a/js/extensionPrefs/ui/extensions-window.ui b/js/extensionPrefs/ui/extensions-window.ui
index 4ac68b9d28..a3068033c3 100644
--- a/js/extensionPrefs/ui/extensions-window.ui
+++ b/js/extensionPrefs/ui/extensions-window.ui
@@ -2,6 +2,44 @@
 <!-- Generated with glade 3.22.0 -->
 <interface>
   <requires lib="gtk+" version="3.20"/>
+  <object class="GtkPopover" id="infoPopover">
+    <child>
+      <object class="GtkBox">
+        <property name="visible">True</property>
+        <property name="orientation">vertical</property>
+        <property name="margin">12</property>
+        <property name="spacing">6</property>
+        <child>
+          <object class="GtkLabel">
+            <property name="visible">True</property>
+            <property name="label" translatable="yes">To find and add extensions, visit &lt;a 
href="https://extensions.gnome.org"&gt;extensions.gnome.org&lt;/a&gt;.</property>
+            <property name="use_markup">True</property>
+            <property name="xalign">0</property>
+          </object>
+        </child>
+        <child>
+          <object class="GtkLabel">
+            <property name="visible">True</property>
+            <property name="label" translatable="yes">Warning</property>
+            <property name="xalign">0</property>
+            <property name="margin_top">6</property>
+            <attributes>
+              <attribute name="weight" value="bold"/>
+            </attributes>
+          </object>
+        </child>
+        <child>
+          <object class="GtkLabel">
+            <property name="visible">True</property>
+            <property name="label" translatable="yes">Extensions can cause system issues, including 
performance problems. If you encounter problems with your system, it is recommended to disable all 
extensions.</property>
+            <property name="wrap">True</property>
+            <property name="max_width_chars">40</property>
+            <property name="xalign">0</property>
+          </object>
+        </child>
+      </object>
+    </child>
+  </object>
   <template class="ExtensionsWindow" parent="GtkApplicationWindow">
     <property name="default_width">800</property>
     <property name="default_height">500</property>
@@ -10,6 +48,18 @@
         <property name="visible">True</property>
         <property name="title" translatable="yes">Shell Extensions</property>
         <property name="show_close_button">True</property>
+        <child>
+          <object class="GtkMenuButton">
+            <property name="visible">True</property>
+            <property name="popover">infoPopover</property>
+            <child>
+              <object class="GtkImage">
+                <property name="visible">True</property>
+                <property name="icon_name">dialog-information-symbolic</property>
+              </object>
+            </child>
+          </object>
+        </child>
         <child>
           <object class="GtkSwitch" id="killSwitch">
             <property name="visible">True</property>