[gnome-builder] style: give theme authors a bit of help

[Christian Hergert <chergert src gnome org>]

commit b0fe0fc16c6f851b2cffb8196871e9e9faf13f24
Author: Christian Hergert <chergert redhat com>
Date:   Wed Dec 20 15:17:40 2017 -0800

    style: give theme authors a bit of help
    
    There is absolutely *NO GUARANTEE* I will not break your theme on
    a daily basis. We allow upstream theming by theme authors that are
    willing to be dilligent and keeping things up to date. Builder is
    largely built with custom widgets and that requires attentiveness
    on the part of those touching the themes.

 src/libide/preferences/ide-preferences-window.ui |    3 +++
 src/libide/workbench/ide-workbench.ui            |    1 +
 2 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/src/libide/preferences/ide-preferences-window.ui 
b/src/libide/preferences/ide-preferences-window.ui
index e2bad0b..e01327f 100644
--- a/src/libide/preferences/ide-preferences-window.ui
+++ b/src/libide/preferences/ide-preferences-window.ui
@@ -1,6 +1,9 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <interface>
   <template class="IdePreferencesWindow" parent="GtkWindow">
+    <style>
+      <class name="org-gnome-Builder"/>
+    </style>
     <child type="titlebar">
       <object class="GtkHeaderBar" id="header_bar">
         <property name="title" translatable="yes">Preferences</property>
diff --git a/src/libide/workbench/ide-workbench.ui b/src/libide/workbench/ide-workbench.ui
index 0c95105..583d2c1 100644
--- a/src/libide/workbench/ide-workbench.ui
+++ b/src/libide/workbench/ide-workbench.ui
@@ -3,6 +3,7 @@
   <!-- interface-requires gtk+ 3.22 -->
   <template class="IdeWorkbench" parent="DzlApplicationWindow">
     <style>
+      <class name="org-gnome-Builder"/>
       <class name="workbench"/>
     </style>
     <child type="titlebar">