[gnome-games] runner: Add supports_savestates property

[Alexander Mikhaylenko <alexm src gnome org>]

commit ad62af7702d43476581c5f4e9c40e7ed14da9510
Author: Yetizone <andreii lisita gmail com>
Date:   Thu Aug 8 11:22:43 2019 +0300

    runner: Add supports_savestates property

 src/command/command-runner.vala | 4 ++++
 src/core/runner.vala            | 1 +
 src/dummy/dummy-runner.vala     | 4 ++++
 src/retro/retro-runner.vala     | 4 ++++
 4 files changed, 13 insertions(+)
---
diff --git a/src/command/command-runner.vala b/src/command/command-runner.vala
index c20664ce..469a25de 100644
--- a/src/command/command-runner.vala
+++ b/src/command/command-runner.vala
@@ -13,6 +13,10 @@ public class Games.CommandRunner : Object, Runner {
                get { return false; }
        }
 
+       public bool supports_savestates {
+               get { return false; }
+       }
+
        public MediaSet? media_set {
                get { return null; }
        }
diff --git a/src/core/runner.vala b/src/core/runner.vala
index f87828f8..c432ddca 100644
--- a/src/core/runner.vala
+++ b/src/core/runner.vala
@@ -6,6 +6,7 @@ public interface Games.Runner : Object {
        public abstract bool can_fullscreen { get; }
        public abstract bool can_quit_safely { get; }
        public abstract bool can_resume { get; }
+       public abstract bool supports_savestates { get; }
        public abstract MediaSet? media_set { get; }
        public abstract InputMode input_mode { get; set; }
 
diff --git a/src/dummy/dummy-runner.vala b/src/dummy/dummy-runner.vala
index 8434e2ae..3434727c 100644
--- a/src/dummy/dummy-runner.vala
+++ b/src/dummy/dummy-runner.vala
@@ -13,6 +13,10 @@ private class Games.DummyRunner : Object, Runner {
                get { return false; }
        }
 
+       public bool supports_savestates {
+               get { return false; }
+       }
+
        public MediaSet? media_set {
                get { return null; }
        }
diff --git a/src/retro/retro-runner.vala b/src/retro/retro-runner.vala
index 4ddba679..432968f5 100644
--- a/src/retro/retro-runner.vala
+++ b/src/retro/retro-runner.vala
@@ -16,6 +16,10 @@ public class Games.RetroRunner : Object, Runner {
                get { return game_savestates.length != 0; }
        }
 
+       public bool supports_savestates {
+               get { return core.get_can_access_state (); }
+       }
+
        private MediaSet _media_set;
        public MediaSet? media_set {
                get { return _media_set; }