[gnome-builder] project-tree: fix project tree styling

[Christian Hergert <chergert src gnome org>]

commit 77b62d2b7bd468ed3826f7679722b47f63a047ec
Author: Christian Hergert <christian hergert me>
Date:   Sat Feb 13 11:12:04 2016 -0800

    project-tree: fix project tree styling

 data/keybindings/default.css           |    2 +-
 data/keybindings/emacs.css             |    2 +-
 data/keybindings/vim.css               |    2 +-
 plugins/project-tree/gb-project-tree.c |    7 ++++---
 4 files changed, 7 insertions(+), 6 deletions(-)
---
diff --git a/data/keybindings/default.css b/data/keybindings/default.css
index 4f71340..668dcf3 100644
--- a/data/keybindings/default.css
+++ b/data/keybindings/default.css
@@ -58,6 +58,6 @@ idesourceviewmode.default {
   -gtk-key-bindings: default-ide-source-view;
 }
 
-projecttree {
+tree.project-tree {
   -gtk-key-bindings: builder-gb-project-tree;
 }
diff --git a/data/keybindings/emacs.css b/data/keybindings/emacs.css
index da463f1..3f97e98 100644
--- a/data/keybindings/emacs.css
+++ b/data/keybindings/emacs.css
@@ -199,7 +199,7 @@ listbox {
   -gtk-key-bindings: builder-emacs-list-box;
 }
 
-projecttree {
+tree.project-tree {
   -gtk-key-bindings: builder-emacs-tree-view,
                      builder-gb-project-tree;
 }
diff --git a/data/keybindings/vim.css b/data/keybindings/vim.css
index 0fe9d6d..3d29631 100644
--- a/data/keybindings/vim.css
+++ b/data/keybindings/vim.css
@@ -2624,7 +2624,7 @@ treeview {
   -gtk-key-bindings: builder-vim-tree-view;
 }
 
-projecttree {
+tree.project-tree {
   -gtk-key-bindings: builder-vim-tree-view,
                      builder-gb-project-tree-vim,
                      builder-gb-project-tree;
diff --git a/plugins/project-tree/gb-project-tree.c b/plugins/project-tree/gb-project-tree.c
index 1bf479c..a788e67 100644
--- a/plugins/project-tree/gb-project-tree.c
+++ b/plugins/project-tree/gb-project-tree.c
@@ -150,7 +150,6 @@ static void
 gb_project_tree_class_init (GbProjectTreeClass *klass)
 {
   GObjectClass *object_class = G_OBJECT_CLASS (klass);
-  GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass);
 
   object_class->finalize = gb_project_tree_finalize;
   object_class->get_property = gb_project_tree_get_property;
@@ -164,16 +163,18 @@ gb_project_tree_class_init (GbProjectTreeClass *klass)
                          (G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
 
   g_object_class_install_properties (object_class, LAST_PROP, properties);
-
-  gtk_widget_class_set_css_name (widget_class, "projecttree");
 }
 
 static void
 gb_project_tree_init (GbProjectTree *self)
 {
+  GtkStyleContext *style_context;
   IdeTreeBuilder *builder;
   GMenu *menu;
 
+  style_context = gtk_widget_get_style_context (GTK_WIDGET (self));
+  gtk_style_context_add_class (style_context, "project-tree");
+
   self->settings = g_settings_new ("org.gnome.builder.project-tree");
 
   g_settings_bind (self->settings, "show-icons",