Fix a panic with dolphin-emu-nogui

That app pops up a window which has neither app_id nor name which I assumed all
windows have.  Now check for pid and shell to determine a con't type as window.

Cargo.lock

@@ -150,9 +150,9 @@ checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
 [[package]]
 name = "libc"
-version = "0.2.107"
+version = "0.2.108"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fbe5e23404da5b4f555ef85ebed98fb4083e55a00c317800bc2a50ede9f3d219"
+checksum = "8521a1b57e76b1ec69af7599e75e38e7b7fad6610f037db8c79b127201b5d119"
 
 [[package]]
 name = "memchr"

src/tree.rs

@@ -93,19 +93,24 @@ impl NodeMethods for s::Node {
                 if self.node_type == s::NodeType::Con
                     && self.name.is_none()
                     && self.app_id.is_none()
+                    && self.pid.is_none()
+                    && self.shell.is_none()
                     && self.window_properties.is_none()
                     && self.layout != s::NodeLayout::None
                 {
                     Type::Container
                 } else if (self.node_type == s::NodeType::Con
                     || self.node_type == s::NodeType::FloatingCon)
-                    && self.name.is_some()
+                    // Apparently there can be windows without app_id, name,
+                    // and window_properties.class, e.g., dolphin-emu-nogui.
+                    && self.pid.is_some()
+                    && self.shell.is_some()
                 {
                     Type::Window
                 } else {
                     panic!(
-                        "Don't know type of node with id {} and node_type {:?}",
+                        "Don't know type of node with id {} and node_type {:?}\n{:?}",
-                        self.id, self.node_type
+                        self.id, self.node_type, self
                     )
                 }
             }