Ensure ARC accessibility focus is on important node

Sometimes Android sends a focus event to non-important node, which makes
ChromeVox focus gets lost.

This CL changes AXTreeSource to adjust focused node to be on an
important node.

Bug: b/148356932
Test: unit_tests --gtest_filter="AXTreeSourceArcTest.*"
Test: manual. Open PlayStore, press install button of an app with in-purchase when touch mode is off. Ensure focus isn't lost.
Change-Id: Ic19796d7b0d7abbeb1ff7a0e72ef3770346b1de1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2086462Reviewed-by: David Tseng <dtseng@chromium.org>
Reviewed-by: Sara Kato <sarakato@chromium.org>
Commit-Queue: Hiroki Sato <hirokisato@chromium.org>
Cr-Commit-Position: refs/heads/master@{#747071}

chrome/browser/chromeos/arc/accessibility/ax_tree_source_arc.cc

@@ -179,6 +179,24 @@ void AXTreeSourceArc::NotifyAccessibilityEvent(AXEventData* event_data) {
     }
   }
 
+  AXNodeInfoData* focused_node =
+      android_focused_id_.has_value()
+          ? GetFromId(*android_focused_id_)->GetNode()
+          : nullptr;
+
+  // Ensure that the focused node correctly gets focus.
+  while (android_focused_id_.has_value() && android_focused_id_ != root_id_ &&
+         !IsImportantInAndroid(focused_node)) {
+    AccessibilityInfoDataWrapper* parent =
+        GetFromId(parent_map_[*android_focused_id_]);
+    if (parent && parent->IsNode()) {
+      android_focused_id_ = parent->GetId();
+      focused_node = parent->GetNode();
+    } else {
+      break;
+    }
+  }
+
   ApplyCachedProperties();
 
   ExtensionMsg_AccessibilityEventBundleParams event_bundle;
@@ -186,13 +204,6 @@ void AXTreeSourceArc::NotifyAccessibilityEvent(AXEventData* event_data) {
 
   event_bundle.events.emplace_back();
   ui::AXEvent& event = event_bundle.events.back();
-
-  // When the focused node exists, give it as a hint to decide a Chrome
-  // automation event type.
-  AXNodeInfoData* focused_node = nullptr;
-  if (android_focused_id_.has_value() &&
-      tree_map_.find(*android_focused_id_) != tree_map_.end())
-    focused_node = tree_map_[*android_focused_id_]->GetNode();
   event.event_type = ToAXEvent(event_data->event_type, focused_node);
   event.id = event_data->source_id;
 

chrome/browser/chromeos/arc/accessibility/ax_tree_source_arc_unittest.cc

@@ -925,6 +925,7 @@ TEST_F(AXTreeSourceArcTest, OnViewSelectedEvent) {
   AXNodeInfoData* button = event->node_data.back().get();
   button->id = 1;
   SetProperty(button, AXBooleanProperty::FOCUSABLE, true);
+  SetProperty(button, AXBooleanProperty::IMPORTANCE, true);
 
   // Ensure that button has a focus.
   event->event_type = AXEventType::VIEW_FOCUSED;
@@ -1255,13 +1256,27 @@ TEST_F(AXTreeSourceArcTest, SyncFocus) {
   SetProperty(node2, AXBooleanProperty::IMPORTANCE, true);
   node2->bounds_in_screen = gfx::Rect(50, 50, 100, 100);
 
-  CallNotifyAccessibilityEvent(event.get());
+  // Add a child node to |node1|, but it's not an important node.
+  SetProperty(node1, AXIntListProperty::CHILD_NODE_IDS, std::vector<int>({3}));
+  event->node_data.emplace_back(AXNodeInfoData::New());
+  AXNodeInfoData* node3 = event->node_data.back().get();
+  node3->id = 3;
 
   // Initially |node1| has a focus.
+  CallNotifyAccessibilityEvent(event.get());
   ui::AXTreeData data;
   EXPECT_TRUE(CallGetTreeData(&data));
   EXPECT_EQ(node1->id, data.focus_id);
 
+  // Focus event to a non-important node. The descendant important node |node1|
+  // gets focus instead.
+  event->source_id = node3->id;
+  event->event_type = AXEventType::VIEW_FOCUSED;
+  CallNotifyAccessibilityEvent(event.get());
+
+  EXPECT_TRUE(CallGetTreeData(&data));
+  EXPECT_EQ(node1->id, data.focus_id);
+
   // Move Chrome accessibility focus to |node2|.
   CallUpdateAccessibilityFocusLocation(node2->id);