Use unique IDs for accessibility nodes on Android

content/browser/accessibility/browser_accessibility_manager_win.cc

 // Copyright (c) 2012 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 "content/browser/accessibility/browser_accessibility_manager_win.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/win/scoped_comptr.h"
 #include "base/win/windows_version.h"
 #include "content/browser/accessibility/browser_accessibility_state_impl.h"
 #include "content/browser/accessibility/browser_accessibility_win.h"
 #include "content/browser/renderer_host/legacy_render_widget_host_win.h"
 #include "content/common/accessibility_messages.h"
 #include "ui/base/win/atl_module.h"
 
 namespace content {
 
-// Map from unique_id_win to BrowserAccessibility
-using UniqueIDWinMap = base::hash_map<LONG, BrowserAccessibility*>;
-base::LazyInstance<UniqueIDWinMap> g_unique_id_map = LAZY_INSTANCE_INITIALIZER;
-
 // static
 BrowserAccessibilityManager* BrowserAccessibilityManager::Create(
     const ui::AXTreeUpdate& initial_tree,
     BrowserAccessibilityDelegate* delegate,
     BrowserAccessibilityFactory* factory) {
   return new BrowserAccessibilityManagerWin(initial_tree, delegate, factory);
 }
 
 BrowserAccessibilityManagerWin*
 BrowserAccessibilityManager::ToBrowserAccessibilityManagerWin() {
@@ skipping 105 matching lines @@
     return;
   }
 
   // If a focus event is needed on the root, fire that first before
   // this event.
   if (event == EVENT_OBJECT_FOCUS && node == GetRoot())
     focus_event_on_root_needed_ = false;
   else if (focus_event_on_root_needed_)
     OnWindowFocused();
 
-  LONG child_id = node->ToBrowserAccessibilityWin()->unique_id_win();
+  // Pass the negation of this node's unique id in the |child_id|
+  // argument to NotifyWinEvent; the AT client will then call get_accChild
+  // on the HWND's accessibility object and pass it that same id, which
+  // we can use to retrieve the IAccessible for this node.
+  LONG child_id = -node->unique_id();
   ::NotifyWinEvent(event, hwnd, OBJID_CLIENT, child_id);
 }
 
 void BrowserAccessibilityManagerWin::OnIAccessible2Used() {
   BrowserAccessibilityStateImpl::GetInstance()->OnScreenReaderDetected();
 }
 
 void BrowserAccessibilityManagerWin::OnWindowFocused() {
   // Make sure we don't call this recursively.
   if (inside_on_window_focused_)
@@ skipping 123 matching lines @@
     }
     default:
       // Not all WebKit accessibility events result in a Windows
       // accessibility notification.
       break;
   }
 
   if (!node)
     return;
 
-  if (event_id != EVENT_MIN) {
-    // Pass the node's unique id in the |child_id| argument to NotifyWinEvent;
-    // the AT client will then call get_accChild on the HWND's accessibility
-    // object and pass it that same id, which we can use to retrieve the
-    // IAccessible for this node.
+  if (event_id != EVENT_MIN)
     MaybeCallNotifyWinEvent(event_id, node);
-  }
+
 
   // If this is a layout complete notification (sent when a container scrolls)
   // and there is a descendant tracked object, send a notification on it.
   // TODO(dmazzoni): remove once http://crbug.com/113483 is fixed.
   if (event_type == ui::AX_EVENT_LAYOUT_COMPLETE &&
       tracked_scroll_object_ &&
       tracked_scroll_object_->IsDescendantOf(node)) {
     MaybeCallNotifyWinEvent(
         IA2_EVENT_VISIBLE_DATA_CHANGED, tracked_scroll_object_);
     tracked_scroll_object_->Release();
     tracked_scroll_object_ = NULL;
   }
 }
 
 void BrowserAccessibilityManagerWin::OnNodeCreated(ui::AXTree* tree,
                                                    ui::AXNode* node) {
   DCHECK(node);
   BrowserAccessibilityManager::OnNodeCreated(tree, node);
   BrowserAccessibility* obj = GetFromAXNode(node);
   if (!obj)
     return;
   if (!obj->IsNative())
     return;
-  LONG unique_id_win = obj->ToBrowserAccessibilityWin()->unique_id_win();
-  g_unique_id_map.Get()[unique_id_win] = obj;
 }
 
 void BrowserAccessibilityManagerWin::OnNodeWillBeDeleted(ui::AXTree* tree,
                                                          ui::AXNode* node) {
   DCHECK(node);
   BrowserAccessibility* obj = GetFromAXNode(node);
   if (obj && obj->IsNative()) {
-    g_unique_id_map.Get().erase(
-        obj->ToBrowserAccessibilityWin()->unique_id_win());
     if (obj == tracked_scroll_object_) {
       tracked_scroll_object_->Release();
       tracked_scroll_object_ = NULL;
     }
   }
 
   // Call the inherited function at the bottom, otherwise our call to
   // |GetFromAXNode|, above, will fail!
   BrowserAccessibilityManager::OnNodeWillBeDeleted(tree, node);
 }
@@ skipping 13 matching lines @@
 
   // Do a sequence of Windows-specific updates on each node. Each one is
   // done in a single pass that must complete before the next step starts.
   // The first step moves win_attributes_ to old_win_attributes_ and then
   // recomputes all of win_attributes_ other than IAccessibleText.
   for (size_t i = 0; i < changes.size(); ++i) {
     const ui::AXNode* changed_node = changes[i].node;
     DCHECK(changed_node);
     BrowserAccessibility* obj = GetFromAXNode(changed_node);
     if (obj && obj->IsNative() && !obj->PlatformIsChildOfLeaf())
-      obj->ToBrowserAccessibilityWin()->UpdateStep1ComputeWinAttributes();
+      ToBrowserAccessibilityWin(obj)->UpdateStep1ComputeWinAttributes();
   }
 
   // The next step updates the hypertext of each node, which is a
   // concatenation of all of its child text nodes, so it can't run until
   // the text of all of the nodes was computed in the previous step.
   for (size_t i = 0; i < changes.size(); ++i) {
     const ui::AXNode* changed_node = changes[i].node;
     DCHECK(changed_node);
     BrowserAccessibility* obj = GetFromAXNode(changed_node);
     if (obj && obj->IsNative() && !obj->PlatformIsChildOfLeaf())
-      obj->ToBrowserAccessibilityWin()->UpdateStep2ComputeHypertext();
+      ToBrowserAccessibilityWin(obj)->UpdateStep2ComputeHypertext();
   }
 
   // The third step fires events on nodes based on what's changed - like
   // if the name, value, or description changed, or if the hypertext had
   // text inserted or removed. It's able to figure out exactly what changed
   // because we still have old_win_attributes_ populated.
   // This step has to run after the previous two steps complete because the
   // client may walk the tree when it receives any of these events.
   // At the end, it deletes old_win_attributes_ since they're not needed
   // anymore.
   for (size_t i = 0; i < changes.size(); ++i) {
     const ui::AXNode* changed_node = changes[i].node;
     DCHECK(changed_node);
     BrowserAccessibility* obj = GetFromAXNode(changed_node);
     if (obj && obj->IsNative() && !obj->PlatformIsChildOfLeaf()) {
-      obj->ToBrowserAccessibilityWin()->UpdateStep3FireEvents(
+      ToBrowserAccessibilityWin(obj)->UpdateStep3FireEvents(
           changes[i].type == AXTreeDelegate::SUBTREE_CREATED);
     }
   }
 }
 
 void BrowserAccessibilityManagerWin::TrackScrollingObject(
     BrowserAccessibilityWin* node) {
   if (tracked_scroll_object_)
     tracked_scroll_object_->Release();
   tracked_scroll_object_ = node;
   tracked_scroll_object_->AddRef();
 }
 
-BrowserAccessibilityWin* BrowserAccessibilityManagerWin::GetFromUniqueIdWin(
-    LONG unique_id_win) {
-  auto iter = g_unique_id_map.Get().find(unique_id_win);
-  if (iter == g_unique_id_map.Get().end())
-    return nullptr;
-
-  return iter->second->ToBrowserAccessibilityWin();
-}
-
 }  // namespace content