[gnome-boxes] app-window: Add Alt+Left shortcut

[Zeeshan Ali Khattak <zeeshanak src gnome org>]

commit 750851147f96d2b9ebc716cf12667cbc35b3bbd9
Author: Lasse Schuirmann <lasse schuirmann net>
Date:   Sat Mar 8 16:09:19 2014 +0100

    app-window: Add Alt+Left shortcut
    
    Add Alt+Left shortcut for
    
    * CREDS
    * PROPERTIES
    
    https://bugzilla.gnome.org/show_bug.cgi?id=725062

 src/app-window.vala |    4 ++++
 src/topbar.vala     |   15 +++++++++++++++
 2 files changed, 19 insertions(+), 0 deletions(-)
---
diff --git a/src/app-window.vala b/src/app-window.vala
index ce59a50..30fc45b 100644
--- a/src/app-window.vala
+++ b/src/app-window.vala
@@ -173,6 +173,10 @@ private class Boxes.AppWindow: Gtk.ApplicationWindow, Boxes.UI {
                    (event.state & default_modifiers) == Gdk.ModifierType.MOD1_MASK) {
             App.app.quit_app ();
             return true;
+        } else if (event.keyval == Gdk.Key.Left && // ALT + Left -> back
+                   (event.state & default_modifiers) == Gdk.ModifierType.MOD1_MASK) {
+            App.window.topbar.click_back_button ();
+            return true;
         }
 
         return false;
diff --git a/src/topbar.vala b/src/topbar.vala
index f72c804..551f36b 100644
--- a/src/topbar.vala
+++ b/src/topbar.vala
@@ -26,6 +26,9 @@ private class Boxes.Topbar: Gtk.Stack, Boxes.UI {
     public Gtk.Button wizard_create_btn;
 
     [GtkChild]
+    private Gtk.Button props_back_btn;
+
+    [GtkChild]
     private Gtk.Button search_btn;
     [GtkChild]
     private Gtk.Button search2_btn;
@@ -51,6 +54,18 @@ private class Boxes.Topbar: Gtk.Stack, Boxes.UI {
 
     private GLib.Binding props_name_bind;
 
+    // Clicks the appropriate back button depending on the ui state.
+    public void click_back_button () {
+        switch (App.app.ui_state) {
+        case UIState.PROPERTIES:
+            props_back_btn.clicked ();
+            break;
+        case UIState.CREDS:
+            back_btn.clicked ();
+            break;
+        }
+    }
+
     public string? _status;
     public string? status {
         get { return _status; }