Expand Chrome OS ARC support to create one tree source per package

chrome/browser/chromeos/arc/accessibility/arc_accessibility_helper_bridge.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/arc_accessibility_helper_bridge.h"
 
 #include "base/command_line.h"
 #include "chrome/browser/chromeos/accessibility/accessibility_manager.h"
-#include "chrome/browser/chromeos/arc/accessibility/ax_tree_source_arc.h"
+#include "chrome/browser/profiles/profile.h"
 #include "chromeos/chromeos_switches.h"
 #include "components/arc/arc_bridge_service.h"
 #include "components/exo/shell_surface.h"
 #include "components/exo/surface.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/window.h"
 #include "ui/gfx/geometry/rect.h"
-#include "ui/views/view.h"
-#include "ui/views/widget/widget.h"
 
 namespace {
 
-// This class keeps focus on a |ShellSurface| without interfering with default
-// focus management in |ShellSurface|. For example, touch causes the
-// |ShellSurface| to lose focus to its ancestor containing View.
-class FocusStealer : public views::View {
- public:
-  explicit FocusStealer(int32_t id) : id_(id) {
-    SetFocusBehavior(views::View::FocusBehavior::ALWAYS);
-    set_owned_by_client();
-  }
-
-  // views::View overrides.
-  void GetAccessibleNodeData(ui::AXNodeData* node_data) override {
-    node_data->AddIntAttribute(ui::AX_ATTR_CHILD_TREE_ID, id_);
-    node_data->role = ui::AX_ROLE_CLIENT;
-  }
-
- private:
-  int32_t id_;
-  DISALLOW_COPY_AND_ASSIGN(FocusStealer);
-};
-
 exo::Surface* GetArcSurface(const aura::Window* window) {
   if (!window)
     return nullptr;
 
   exo::Surface* arc_surface = exo::Surface::AsSurface(window);
   if (!arc_surface)
     arc_surface = exo::ShellSurface::GetMainSurface(window);
   return arc_surface;
 }
 
+int32_t GetTaskId(aura::Window* window) {
+  const std::string arc_app_id = exo::ShellSurface::GetApplicationId(window);
+  if (arc_app_id.empty())
+    return -1;

[dmazzoni, 2017/04/25 16:09:24]

how about kNoTaskId?

[David Tseng, 2017/04/25 22:48:03]

Done.

+
+  int task_id = -1;
+  if (sscanf(arc_app_id.c_str(), "org.chromium.arc.%d", &task_id) != 1)
+    return -1;
+
+  return task_id;
+}
+
 void DispatchFocusChange(arc::mojom::AccessibilityNodeInfoData* node_data) {
   chromeos::AccessibilityManager* accessibility_manager =
       chromeos::AccessibilityManager::Get();
   if (!accessibility_manager)
     return;
 
   exo::WMHelper* wmHelper = exo::WMHelper::GetInstance();
   aura::Window* focused_window = wmHelper->GetFocusedWindow();
   if (!focused_window)
     return;
 
   aura::Window* toplevel_window = focused_window->GetToplevelWindow();
 
   gfx::Rect bounds_in_screen = gfx::ScaleToEnclosingRect(
       node_data->boundsInScreen,
       1.0f / toplevel_window->layer()->device_scale_factor());
 
   accessibility_manager->OnViewFocusedInArc(bounds_in_screen);
 }
 
+arc::mojom::AccessibilityFilterType GetFilterType() {
+  chromeos::AccessibilityManager* accessibility_manager =
+      chromeos::AccessibilityManager::Get();
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          chromeos::switches::kEnableChromeVoxArcSupport))
+    return arc::mojom::AccessibilityFilterType::ALL;
+
+  if (!accessibility_manager)
+    return arc::mojom::AccessibilityFilterType::OFF;
+
+  if (accessibility_manager->IsSpokenFeedbackEnabled())
+    return arc::mojom::AccessibilityFilterType::WHITELISTED_PACKAGE_NAME;
+
+  if (accessibility_manager->IsFocusHighlightEnabled())
+    return arc::mojom::AccessibilityFilterType::FOCUS;
+
+  return arc::mojom::AccessibilityFilterType::OFF;
+}
+
 }  // namespace
 
 namespace arc {
 
 ArcAccessibilityHelperBridge::ArcAccessibilityHelperBridge(
     ArcBridgeService* bridge_service)
-    : ArcService(bridge_service), binding_(this) {
+    : ArcService(bridge_service), binding_(this), current_task_id_(0) {
   arc_bridge_service()->accessibility_helper()->AddObserver(this);
 }
 
 ArcAccessibilityHelperBridge::~ArcAccessibilityHelperBridge() {
   arc_bridge_service()->accessibility_helper()->RemoveObserver(this);
+  ArcAppListPrefs::Get(chromeos::AccessibilityManager::Get()->profile())
+      ->RemoveObserver(this);
 }
 
 void ArcAccessibilityHelperBridge::OnInstanceReady() {
+  ArcAppListPrefs::Get(chromeos::AccessibilityManager::Get()->profile())
+      ->AddObserver(this);
   auto* instance = ARC_GET_INSTANCE_FOR_METHOD(
       arc_bridge_service()->accessibility_helper(), Init);
   DCHECK(instance);
   instance->Init(binding_.CreateInterfacePtrAndBind());
 
-  chromeos::AccessibilityManager* accessibility_manager =
-      chromeos::AccessibilityManager::Get();
-  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
-          chromeos::switches::kEnableChromeVoxArcSupport)) {
-    instance->SetFilter(arc::mojom::AccessibilityFilterType::ALL);
-    if (!tree_source_) {
-      tree_source_.reset(new AXTreeSourceArc(tree_id()));
-      focus_stealer_.reset(new FocusStealer(tree_source_->tree_id()));
-      exo::WMHelper::GetInstance()->AddActivationObserver(this);
-    }
-  } else if (accessibility_manager &&
-             accessibility_manager->IsFocusHighlightEnabled()) {
-    instance->SetFilter(arc::mojom::AccessibilityFilterType::FOCUS);
-  }
+  arc::mojom::AccessibilityFilterType filter_type = GetFilterType();
+  instance->SetFilter(filter_type);
+
+  if (filter_type == arc::mojom::AccessibilityFilterType::ALL ||
+      filter_type ==
+          arc::mojom::AccessibilityFilterType::WHITELISTED_PACKAGE_NAME)
+    exo::WMHelper::GetInstance()->AddActivationObserver(this);
 }
 
 void ArcAccessibilityHelperBridge::OnAccessibilityEventDeprecated(
     mojom::AccessibilityEventType event_type,
     mojom::AccessibilityNodeInfoDataPtr event_source) {
   if (event_type == arc::mojom::AccessibilityEventType::VIEW_FOCUSED)
     DispatchFocusChange(event_source.get());
 }
 
 void ArcAccessibilityHelperBridge::OnAccessibilityEvent(
     mojom::AccessibilityEventDataPtr event_data) {
-  if (tree_source_) {
-    tree_source_->NotifyAccessibilityEvent(event_data.get());
+  arc::mojom::AccessibilityFilterType filter_type = GetFilterType();
+
+  if (filter_type == arc::mojom::AccessibilityFilterType::ALL ||
+      filter_type ==
+          arc::mojom::AccessibilityFilterType::WHITELISTED_PACKAGE_NAME) {
+    // Get the task id for this package.
+    if (event_data->nodeData.size()) {

[dmazzoni, 2017/04/25 16:09:24]

nit: early-exit if the size is zero instead, to avoid nesting

[David Tseng, 2017/04/25 22:48:03]

Done.

+      arc::mojom::AccessibilityNodeInfoData* node =
+          event_data->nodeData[0].get();
+      if (!node->stringProperties)
+        return;
+
+      auto it = node->stringProperties->find(
+          arc::mojom::AccessibilityStringProperty::PACKAGE_NAME);
+      if (it == node->stringProperties->end())
+        return;
+
+      auto task_id_it = package_name_to_task_id_.find(it->second);
+      if (task_id_it == package_name_to_task_id_.end())
+        return;
+
+      int32_t task_id = task_id_it->second;
+
+      // Reject updates to non-current task ids. We can do this currently
+      // because all events include the entire tree.
+      if (task_id != current_task_id_)
+        return;
+
+      auto tree_it = task_id_to_tree_.find(task_id);
+      AXTreeSourceArc* tree_source;
+      if (tree_it == task_id_to_tree_.end()) {
+        tree_source = new AXTreeSourceArc(this);
+        task_id_to_tree_[task_id] = tree_source;
+      } else {
+        tree_source = tree_it->second;
+      }
+      tree_source->NotifyAccessibilityEvent(event_data.get());
+    }
     return;
   }
 
   if (event_data->eventType != arc::mojom::AccessibilityEventType::VIEW_FOCUSED)
     return;
 
   CHECK_EQ(1U, event_data.get()->nodeData.size());
   DispatchFocusChange(event_data.get()->nodeData[0].get());
 }
 
-void ArcAccessibilityHelperBridge::OnWindowActivated(
-    aura::Window* gained_active,
-    aura::Window* lost_active) {
-  if (gained_active == lost_active || !tree_source_)
-    return;
-
-  exo::Surface* active_surface = GetArcSurface(gained_active);
-  exo::Surface* inactive_surface = GetArcSurface(lost_active);
-
-  // Detach the accessibility tree from an inactive ShellSurface so that any
-  // client walking the desktop tree gets non-duplicated linearization.
-  if (inactive_surface) {
-    views::Widget* widget = views::Widget::GetWidgetForNativeView(lost_active);
-    if (widget && widget->GetContentsView()) {
-      views::View* view = widget->GetContentsView();
-      view->RemoveChildView(focus_stealer_.get());
-      view->NotifyAccessibilityEvent(ui::AX_EVENT_CHILDREN_CHANGED, false);
-    }
-  }
-
-  if (!active_surface)
-    return;
-
-  views::Widget* widget = views::Widget::GetWidgetForNativeView(gained_active);
-  if (widget && widget->GetContentsView()) {
-    views::View* view = widget->GetContentsView();
-    if (!view->Contains(focus_stealer_.get()))
-      view->AddChildView(focus_stealer_.get());
-    focus_stealer_->RequestFocus();
-    view->NotifyAccessibilityEvent(ui::AX_EVENT_CHILDREN_CHANGED, false);
-  }
-}
-
-void ArcAccessibilityHelperBridge::PerformAction(const ui::AXActionData& data) {
+void ArcAccessibilityHelperBridge::OnAction(const ui::AXActionData& data) {
   arc::mojom::AccessibilityActionType mojo_action;
   switch (data.action) {
     case ui::AX_ACTION_DO_DEFAULT:
       mojo_action = arc::mojom::AccessibilityActionType::CLICK;
       break;
     default:
       return;
   }
 
   auto* instance = ARC_GET_INSTANCE_FOR_METHOD(
       arc_bridge_service()->accessibility_helper(), PerformAction);
   instance->PerformAction(data.target_node_id, mojo_action);
 }
 
+void ArcAccessibilityHelperBridge::OnWindowActivated(
+    aura::Window* gained_active,
+    aura::Window* lost_active) {
+  if (gained_active == lost_active)
+    return;
+
+  if (!GetArcSurface(gained_active))
+    return;
+
+  // Grab the tree source associated with this app.
+  int32_t task_id = GetTaskId(gained_active);
+  auto it = task_id_to_tree_.find(task_id);
+  if (it != task_id_to_tree_.end())
+    it->second->Focus(gained_active);
+}
+
+void ArcAccessibilityHelperBridge::OnTaskCreated(
+    int task_id,
+    const std::string& package_name,
+    const std::string& activity,
+    const std::string& intent) {
+  package_name_to_task_id_[package_name] = task_id;

[dmazzoni, 2017/04/25 16:09:25]

DCHECK that the package name doesn't already have a different task id?
Is that possible, do we know for sure it's a 1:1 mapping?

[David Tseng, 2017/04/25 22:48:03]

It's possible for the package name / task id to be removed (OnTaskDestroyed).
Added code to remove the entry given the task id.

Overall, it looks like, at least for the purposes of ArcAppListPrefs::Observer,
we only ever get one task id per package name. I've asked Yuki to confirm. I
wasn't seeing new tasks being created when navigating to new activities within
the same package though.

+}
+
+void ArcAccessibilityHelperBridge::OnTaskDestroyed(int task_id) {
+  auto it = task_id_to_tree_.find(task_id);
+  if (it != task_id_to_tree_.end()) {
+    delete it->second;
+    task_id_to_tree_.erase(it);
+  }
+}
+
+void ArcAccessibilityHelperBridge::OnTaskSetActive(int32_t task_id) {
+  current_task_id_ = task_id;
+}
+
 }  // namespace arc