Initial support for native accessibility in ARC

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

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/chromeos/arc/accessibility/ax_tree_source_arc.h"
+
+#include "chrome/browser/extensions/api/automation_internal/automation_event_router.h"
+#include "chrome/browser/ui/aura/accessibility/automation_manager_aura.h"
+#include "chrome/common/extensions/chrome_extension_messages.h"
+#include "components/exo/wm_helper.h"
+#include "ui/accessibility/ax_tree_id_registry.h"
+#include "ui/aura/window.h"
+
+namespace {
+
+ui::AXEvent ToAXEvent(arc::mojom::AccessibilityEventType arc_event_type) {
+  switch (arc_event_type) {
+    case arc::mojom::AccessibilityEventType::VIEW_FOCUSED:
+    case arc::mojom::AccessibilityEventType::VIEW_ACCESSIBILITY_FOCUSED:
+      return ui::AX_EVENT_FOCUS;
+    case arc::mojom::AccessibilityEventType::VIEW_ACCESSIBILITY_FOCUS_CLEARED:
+      return ui::AX_EVENT_BLUR;
+    case arc::mojom::AccessibilityEventType::VIEW_CLICKED:
+    case arc::mojom::AccessibilityEventType::VIEW_LONG_CLICKED:
+      return ui::AX_EVENT_CLICKED;
+    case arc::mojom::AccessibilityEventType::VIEW_TEXT_CHANGED:
+      return ui::AX_EVENT_TEXT_CHANGED;
+    case arc::mojom::AccessibilityEventType::VIEW_TEXT_SELECTION_CHANGED:
+      return ui::AX_EVENT_TEXT_SELECTION_CHANGED;
+    case arc::mojom::AccessibilityEventType::WINDOW_STATE_CHANGED:
+    case arc::mojom::AccessibilityEventType::NOTIFICATION_STATE_CHANGED:
+    case arc::mojom::AccessibilityEventType::WINDOW_CONTENT_CHANGED:
+    case arc::mojom::AccessibilityEventType::WINDOWS_CHANGED:
+      return ui::AX_EVENT_LAYOUT_COMPLETE;
+    case arc::mojom::AccessibilityEventType::VIEW_HOVER_ENTER:
+      return ui::AX_EVENT_FOCUS;
+    case arc::mojom::AccessibilityEventType::ANNOUNCEMENT:
+      return ui::AX_EVENT_ALERT;
+    case arc::mojom::AccessibilityEventType::VIEW_SELECTED:
+    case arc::mojom::AccessibilityEventType::VIEW_HOVER_EXIT:
+    case arc::mojom::AccessibilityEventType::TOUCH_EXPLORATION_GESTURE_START:
+    case arc::mojom::AccessibilityEventType::TOUCH_EXPLORATION_GESTURE_END:
+    case arc::mojom::AccessibilityEventType::VIEW_SCROLLED:
+    case arc::mojom::AccessibilityEventType::
+        VIEW_TEXT_TRAVERSED_AT_MOVEMENT_GRANULARITY:
+    case arc::mojom::AccessibilityEventType::GESTURE_DETECTION_START:
+    case arc::mojom::AccessibilityEventType::GESTURE_DETECTION_END:
+    case arc::mojom::AccessibilityEventType::TOUCH_INTERACTION_START:
+    case arc::mojom::AccessibilityEventType::TOUCH_INTERACTION_END:
+    case arc::mojom::AccessibilityEventType::VIEW_CONTEXT_CLICKED:
+    case arc::mojom::AccessibilityEventType::ASSIST_READING_CONTEXT:
+      return ui::AX_EVENT_CHILDREN_CHANGED;
+    default:
+      return ui::AX_EVENT_CHILDREN_CHANGED;
+  }
+  return ui::AX_EVENT_CHILDREN_CHANGED;
+}
+
+}  // namespace
+
+namespace arc {
+
+AXTreeSourceArc::AXTreeSourceArc()
+    : id_(ui::AXTreeIDRegistry::GetInstance()->CreateID()),
+      current_tree_serializer_(new AXTreeArcSerializer(this)),
+      root_id_(-1),
+      focused_node_id_(-1) {
+  set_owned_by_client();
+  SetFocusBehavior(views::View::FocusBehavior::ALWAYS);
+}
+
+AXTreeSourceArc::~AXTreeSourceArc() {
+  Reset();
+}
+
+void AXTreeSourceArc::NotifyAccessibilityEvent(
+    mojom::AccessibilityEventData* event_data) {
+  tree_map_.clear();
+  parent_map_.clear();
+  for (size_t i = 0; i < event_data->nodeData.size(); ++i) {
+    for (size_t j = 0; j < event_data->nodeData[i]->childIds.size(); ++j)
+      parent_map_[event_data->nodeData[i]->childIds[j]] =
+          event_data->nodeData[i]->id;
+  }
+
+  for (size_t i = 0; i < event_data->nodeData.size(); ++i) {
+    int32_t id = event_data->nodeData[i]->id;
+    tree_map_[id] = event_data->nodeData[i].get();
+    if (parent_map_.find(id) == parent_map_.end())
+      root_id_ = id;

[dmazzoni, 2017/02/09 01:18:09]

Any other clue that we have the root?

Maybe assert that you don't get two roots?

[yawano, 2017/02/09 10:55:29]

Can we simply force that the first element in the list must be the root node of
the tree?

+  }
+
+  ExtensionMsg_AccessibilityEventParams params;
+  current_tree_serializer_->SerializeChanges(GetFromId(event_data->sourceId),
+                                             &params.update);
+  params.tree_id = id_;
+  params.id = event_data->sourceId;
+  params.event_type = ToAXEvent(event_data->eventType);
+  if (params.event_type == ui::AX_EVENT_FOCUS)
+    focused_node_id_ = params.id;
+
+  extensions::AutomationEventRouter* router =
+      extensions::AutomationEventRouter::GetInstance();
+  router->DispatchAccessibilityEvent(params);
+}
+
+bool AXTreeSourceArc::GetTreeData(ui::AXTreeData* data) const {
+  data->tree_id = id_;
+  if (focused_node_id_ >= 0)
+    data->focus_id = focused_node_id_;
+  return true;
+}
+
+mojom::AccessibilityNodeInfoData* AXTreeSourceArc::GetRoot() const {
+  mojom::AccessibilityNodeInfoData* root = GetFromId(root_id_);
+  return root;
+}
+
+mojom::AccessibilityNodeInfoData* AXTreeSourceArc::GetFromId(int32_t id) const {
+  auto it = tree_map_.find(id);
+  if (it == tree_map_.end())
+    return nullptr;
+  return it->second;
+}
+
+int32_t AXTreeSourceArc::GetId(mojom::AccessibilityNodeInfoData* node) const {
+  if (!node)
+    return -1;
+  return node->id;
+}
+
+void AXTreeSourceArc::GetChildren(
+    mojom::AccessibilityNodeInfoData* node,
+    std::vector<mojom::AccessibilityNodeInfoData*>* out_children) const {
+  if (!node)
+    return;
+  for (size_t i = 0; i < node->childIds.size(); ++i) {
+    out_children->push_back(GetFromId(node->childIds[i]));
+  }
+}
+
+mojom::AccessibilityNodeInfoData* AXTreeSourceArc::GetParent(
+    mojom::AccessibilityNodeInfoData* node) const {
+  if (!node)
+    return nullptr;
+  auto it = parent_map_.find(node->id);
+  if (it != parent_map_.end())
+    return GetFromId(it->second);
+  return nullptr;
+}
+
+bool AXTreeSourceArc::IsValid(mojom::AccessibilityNodeInfoData* node) const {
+  return node;
+}
+
+bool AXTreeSourceArc::IsEqual(mojom::AccessibilityNodeInfoData* node1,
+                              mojom::AccessibilityNodeInfoData* node2) const {
+  if (!node1 || !node2)
+    return false;
+  return node1->id == node2->id;
+}
+
+mojom::AccessibilityNodeInfoData* AXTreeSourceArc::GetNull() const {
+  return nullptr;
+}
+
+void AXTreeSourceArc::SerializeNode(mojom::AccessibilityNodeInfoData* node,
+                                    ui::AXNodeData* out_data) const {
+  if (!node)
+    return;
+  out_data->id = node->id;
+  out_data->state = 0;
+  if (!node->text.empty())
+    out_data->SetName(node->text);
+  else if (!node->contentDescription.empty())
+    out_data->SetName(node->contentDescription);
+
+  int32_t id = node->id;
+  if (id == root_id_)
+    out_data->role = ui::AX_ROLE_ROOT_WEB_AREA;
+  else if (!node->text.empty())
+    out_data->role = ui::AX_ROLE_STATIC_TEXT;
+  else
+    out_data->role = ui::AX_ROLE_DIV;
+
+  exo::WMHelper* wmHelper = exo::WMHelper::GetInstance();
+  aura::Window* focused_window = wmHelper->GetFocusedWindow();

[dmazzoni, 2017/02/09 01:18:09]

Maybe try to refactor this out and not call it on every node?

+  gfx::Rect bounds_in_screen = node->boundsInScreen;
+  if (focused_window) {
+    aura::Window* toplevel_window = focused_window->GetToplevelWindow();
+    bounds_in_screen = gfx::ScaleToEnclosingRect(
+        bounds_in_screen,
+        1.0f / toplevel_window->layer()->device_scale_factor());
+  }
+  out_data->location.SetRect(bounds_in_screen.x(), bounds_in_screen.y(),
+                             bounds_in_screen.width(),
+                             bounds_in_screen.height());
+}
+
+void AXTreeSourceArc::GetAccessibleNodeData(ui::AXNodeData* node_data) {
+  node_data->AddIntAttribute(ui::AX_ATTR_CHILD_TREE_ID, id_);
+  node_data->SetName("ExoShell");
+}
+
+void AXTreeSourceArc::Reset() {
+  tree_map_.clear();
+  parent_map_.clear();
+  current_tree_serializer_.reset(new AXTreeArcSerializer(this));
+  extensions::AutomationEventRouter* router =
+      extensions::AutomationEventRouter::GetInstance();
+  router->DispatchTreeDestroyedEvent(id_, nullptr);
+}
+
+}  // namespace arc