add test; clean-up

Author: yjbanov

lib/web_ui/lib/src/engine/semantics/dialog.dart

@@ -21,7 +21,7 @@ class Dialog extends PrimaryRoleManager {
     // focus on something inside it. There could be two possibilities:
     //
     // 1. The framework explicitly marked a node inside the dialog as focused
-    //    via the `isFocusabe` and `isFocused` flags. In this case, the node
+    //    via the `isFocusable` and `isFocused` flags. In this case, the node
     //    will request focus directly and there's nothing to do on top of that.
     // 2. No node inside the route takes focus explicitly. In this case, the
     //    expectation is to look through all nodes in traversal order and focus
@@ -45,7 +45,7 @@ class Dialog extends PrimaryRoleManager {
       }
 
       // If the node does not take focus (e.g. focusing on it does not make
-      // sense at all), depair not. Keep looking.
+      // sense at all). Despair not. Keep looking.
       final bool didTakeFocus = roleManager.focusAsRouteDefault();
       return !didTakeFocus;
     });
@@ -94,7 +94,7 @@ class Dialog extends PrimaryRoleManager {
   @override
   bool focusAsRouteDefault() {
     // Dialogs are the ones that look inside themselves to find elements to
-    // focus one. It doesn't make sense to focus on the dialog itself.
+    // focus on. It doesn't make sense to focus on the dialog itself.
     return false;
   }
 }

lib/web_ui/lib/src/engine/semantics/focusable.dart

@@ -34,8 +34,16 @@ class Focusable extends RoleManager {
 
   final AccessibilityFocusManager _focusManager;
 
+  /// Requests focus as a result of a route (e.g. dialog) deciding that the node
+  /// managed by this class should be focused by default when nothing requests
+  /// focus explicitly.
+  ///
+  /// This method of taking focus is different from the regular method of using
+  /// the [SemanticsObject.hasFocus] flag, as in this case the framework is not
+  /// explicitly request focus. Instead, the DOM element is being focus directly
+  /// programmatically, simulating the screen reader choosing a default element
+  /// to focus on.
   bool focusAsRouteDefault() {
-    print('>>> ${semanticsObject.id} is taking default route focus (label: ${semanticsObject.label})');
     owner.element.focus();
     return true;
   }
@@ -237,7 +245,6 @@ class AccessibilityFocusManager {
         return;
       }
 
-      print('>>> calling focus on ${target.element} id="${target.element.id}"');
       target.element.focus();
     });
   }

lib/web_ui/lib/src/engine/semantics/semantics.dart

@@ -643,22 +643,27 @@ final class GenericRole extends PrimaryRoleManager {
 
   @override
   bool focusAsRouteDefault() {
-    final Focusable? focusable = this.focusable;
-
-    if (focusable != null) {
-      return focusable.focusAsRouteDefault();
+    // Case 1: current node has input focus. Let the input focus system decide
+    // default focusability.
+    if (semanticsObject.isFocusable) {
+      final Focusable? focusable = this.focusable;
+      if (focusable != null) {
+        return focusable.focusAsRouteDefault();
+      }
     }
 
+    // Case 2: current node is not focusable, but just a container of other
+    // nodes or lacks a label. Do not focus on it and let the search continue.
     if (semanticsObject.hasChildren || !semanticsObject.hasLabel) {
-      // Unless the container is explicitly focusable (handled above), do not
-      // autofocus on the container itself. Instead, look for a child to focus
-      // on.
       return false;
     }
 
+    // Case 3: current node is visual/informational. Move just the
+    // accessibility focus.
+
     // Plain text nodes should not be focusable via keyboard or mouse. They are
     // only focusable for the purposes of focusing the screen reader. To achieve
-    // that -1 is used.
+    // this the -1 value is used.
     //
     // See also:
     //
@@ -1773,7 +1778,6 @@ class SemanticsObject {
     final bool shouldContinueVisiting = callback(this);
 
     if (!shouldContinueVisiting) {
-      print('>>> ${primaryRole?.runtimeType} stopped visitDepthFirstInTraversalOrder');
       return false;
     }