keyboard: introduce CcKeyboardShortcutEditor

The current CcKeyboardPanel used to manage keyboard
editing through GtkCellRendererAccel, which was replaced
when we moved to use a GtkListBox. Because of that,
the ability to edit shortcuts is now missing.

Re-add shortcut editing capabilities through a new dialog,
which is done according to the latest mockups available.

https://bugzilla.gnome.org/show_bug.cgi?id=769063

panels/keyboard/cc-keyboard-shortcut-editor.h

@@ -0,0 +1,56 @@
+/* cc-keyboard-shortcut-editor.h
+ *
+ * Copyright (C) 2016 Endless, Inc
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Georges Basile Stavracas Neto <georges.stavracas@gmail.com>
+ */
+
+#ifndef CC_KEYBOARD_SHORTCUT_EDITOR_H
+#define CC_KEYBOARD_SHORTCUT_EDITOR_H
+
+#include <gtk/gtk.h>
+
+#include "cc-keyboard-item.h"
+#include "cc-keyboard-panel.h"
+
+G_BEGIN_DECLS
+
+#define CC_TYPE_KEYBOARD_SHORTCUT_EDITOR (cc_keyboard_shortcut_editor_get_type())
+
+typedef enum
+{
+  CC_SHORTCUT_EDITOR_CREATE,
+  CC_SHORTCUT_EDITOR_EDIT
+} CcShortcutEditorMode;
+
+G_DECLARE_FINAL_TYPE (CcKeyboardShortcutEditor, cc_keyboard_shortcut_editor, CC, KEYBOARD_SHORTCUT_EDITOR, GtkDialog)
+
+GtkWidget*           cc_keyboard_shortcut_editor_new             (CcKeyboardPanel          *panel);
+
+CcKeyboardItem*      cc_keyboard_shortcut_editor_get_item        (CcKeyboardShortcutEditor *self);
+
+void                 cc_keyboard_shortcut_editor_set_item        (CcKeyboardShortcutEditor *self,
+                                                                  CcKeyboardItem           *item);
+
+CcShortcutEditorMode cc_keyboard_shortcut_editor_get_mode        (CcKeyboardShortcutEditor *self);
+
+void                 cc_keyboard_shortcut_editor_set_mode        (CcKeyboardShortcutEditor *self,
+                                                                  CcShortcutEditorMode      mode);
+
+G_END_DECLS
+
+#endif /* CC_KEYBOARD_SHORTCUT_EDITOR_H */
+