[fuchsia][a11y] Fills scroll offsets in semantic nodes.

Nodes that are scrollable containers contain scroll offset data. This
change fills these offsets when converting to a Fuchsia node.

Test: AXTreeConverterTest.*
Bug: fuchsia:60263
Change-Id: Ie0a16e7f326cb0f37097fca9f22dfe11c24d27b2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2490250
Commit-Queue: Lucas Radaelli <lucasradaelli@google.com>
Reviewed-by: Sergey Ulanov <sergeyu@chromium.org>
Reviewed-by: Sharon Yang <yangsharon@chromium.org>
Cr-Commit-Position: refs/heads/master@{#821867}

fuchsia/engine/browser/ax_tree_converter.cc

@@ -145,6 +145,14 @@ fuchsia::accessibility::semantics::States ConvertStates(
         node.GetFloatAttribute(ax::mojom::FloatAttribute::kValueForRange));
   }
 
+  // The scroll offsets, if the element is a scrollable container.
+  const auto x_scroll_offset =
+      node.GetIntAttribute(ax::mojom::IntAttribute::kScrollX);
+  const auto y_scroll_offset =
+      node.GetIntAttribute(ax::mojom::IntAttribute::kScrollY);
+  if (x_scroll_offset || y_scroll_offset)
+    states.set_viewport_offset({x_scroll_offset, y_scroll_offset});
+
   return states;
 }
 

fuchsia/engine/browser/ax_tree_converter_unittest.cc

@@ -91,7 +91,9 @@ std::pair<ui::AXNodeData, Node> CreateSemanticNodeAllFieldsSet() {
       std::vector<int32_t>{kChildId1, kChildId2, kChildId3}, relative_bounds,
       kLabel1, kDescription1, ax::mojom::CheckedState::kMixed);
   ax_node_data.AddBoolAttribute(ax::mojom::BoolAttribute::kSelected, false);
+  ax_node_data.AddIntAttribute(ax::mojom::IntAttribute::kScrollX, 10);
   ax_node_data.RemoveState(ax::mojom::State::kIgnored);
+  ax_node_data.AddIntAttribute(ax::mojom::IntAttribute::kScrollY, 20);
   ax_node_data.id = kChildId1;
 
   Attributes attributes;
@@ -107,6 +109,7 @@ std::pair<ui::AXNodeData, Node> CreateSemanticNodeAllFieldsSet() {
   states.set_checked_state(CheckedState::MIXED);
   states.set_hidden(false);
   states.set_selected(false);
+  states.set_viewport_offset({10, 20});
   auto fuchsia_node = CreateSemanticNode(
       ConvertToFuchsiaNodeId(ax_node_data.id, kRootId), Role::BUTTON,
       std::move(attributes), std::move(states),