Refactor MinimalWindowManager::advise_new_window according to feedback

Mainly, reduced the calls to `Impl::prevent_focus_stealing` and
`Impl::ApplicationSelector::advise_new_window` to one call. And renamed
things to be easier to understand.

src/miral/minimal_window_manager.cpp

@@ -104,7 +104,12 @@ struct miral::MinimalWindowManager::Impl
 
     void apply_resize_by(Displacement movement);
 
-    bool prevent_focus_stealing(WindowInfo const& info);
+    // Returns true if the window should NOT be in focus
+    // Relevant for focus stealing prevention where windows are focused on
+    // launch in specific circumstances.
+    bool should_prevent_focus(WindowInfo const& info);
+
+    bool advise_new_window(WindowInfo const& info);
 
     MirInputEventModifier const pointer_drag_modifier;
     FocusStealing const focus_stealing;
@@ -147,7 +152,7 @@ auto miral::MinimalWindowManager::place_new_window(
 
 void miral::MinimalWindowManager::handle_window_ready(WindowInfo& window_info)
 {
-    if (!self->prevent_focus_stealing(window_info) && window_info.can_be_active())
+    if (!self->should_prevent_focus(window_info) && window_info.can_be_active())
     {
         tools.select_active_window(window_info.window());
     }
@@ -297,16 +302,14 @@ auto miral::MinimalWindowManager::confirm_inherited_move(WindowInfo const& windo
 
 void miral::MinimalWindowManager::advise_new_window(miral::WindowInfo const& window_info)
 {
+    auto should_receive_focus = self->advise_new_window(window_info);
+
     // If the window is prevented from stealing focus, swap the old focused
     // window (now in the back) with the new window in the front.
     //
     // If it's a legitimate window, it'll be focused and raised via
-    // xdg-activation.
-    auto in_background = self->prevent_focus_stealing(window_info);
-
-    self->application_selector.advise_new_window(window_info, in_background);
-
-    if (in_background)
+    // xdg-activation later on.
+    if (!should_receive_focus)
         tools.swap_tree_order(tools.active_window(), window_info.window());
 }
 
@@ -638,11 +641,19 @@ void miral::MinimalWindowManager::Impl::apply_resize_by(Displacement movement)
     }
 }
 
-bool miral::MinimalWindowManager::Impl::prevent_focus_stealing(miral::WindowInfo const& info)
+bool miral::MinimalWindowManager::Impl::should_prevent_focus(miral::WindowInfo const& info)
 {
     auto const without_parent = !info.parent();
     auto const decoration_surface = info.type() == mir_window_type_decoration;
     return (focus_stealing == FocusStealing::prevent) && tools.active_window() &&
            (without_parent || decoration_surface) && info.depth_layer() == mir_depth_layer_application &&
            tools.active_window().application() != info.window().application();
 }
+
+bool miral::MinimalWindowManager::Impl::advise_new_window(WindowInfo const& info)
+{
+    auto should_receive_focus = !should_prevent_focus(info);
+    application_selector.advise_new_window(info, should_receive_focus);
+
+    return should_receive_focus;
+}