[polari] ui: Get rid of custom headerbar classes

[Florian Müllner <fmuellner src gnome org>]

commit fa49e1249d97564552ceda66db85abe7d79d9b21
Author: Florian Müllner <fmuellner gnome org>
Date:   Wed Dec 23 22:58:56 2015 +0100

    ui: Get rid of custom headerbar classes
    
    CSS is expressive enough so we don't need them.

 data/resources/application.css |    3 ++-
 data/resources/main-window.ui  |    6 ------
 2 files changed, 2 insertions(+), 7 deletions(-)
---
diff --git a/data/resources/application.css b/data/resources/application.css
index ca66f67..17b0a9c 100644
--- a/data/resources/application.css
+++ b/data/resources/application.css
@@ -102,7 +102,8 @@
     padding: 6px;
 }
 
-.polari-titlebar-left {
+.titlebar headerbar:dir(ltr):first-child,
+.titlebar headerbar:dir(rtl):last-child {
     /* the horizontal padding confuses left_side_size_group, so we
        add it as margin-left to the first button instead (in mainWindow.ui);
        also set the vertical padding to 0 so the separator extends to the
diff --git a/data/resources/main-window.ui b/data/resources/main-window.ui
index 2067a8b..78a38b5 100644
--- a/data/resources/main-window.ui
+++ b/data/resources/main-window.ui
@@ -20,9 +20,6 @@
             <property name="visible">True</property>
             <property name="hexpand">False</property>
             <property name="show-close-button">True</property>
-            <style>
-              <class name="polari-titlebar-left"/>
-            </style>
             <child>
               <object class="GtkButton" id="joinButton">
                 <property name="visible">True</property>
@@ -70,9 +67,6 @@
             <property name="visible">True</property>
             <property name="hexpand">True</property>
             <property name="show-close-button">True</property>
-            <style>
-              <class name="polari-titlebar-right"/>
-            </style>
             <!-- Use a custom title widget to enable markup for subtitles
                  (for URLs in channel topics); other than that, we want
                  the default GtkHeaderBar behavior, e.g. the subtitle may