Re-land: Send Windows accessibility events based on tree updates.

content/browser/accessibility/browser_accessibility_manager.cc

Index: content/browser/accessibility/browser_accessibility_manager.cc
diff --git a/content/browser/accessibility/browser_accessibility_manager.cc b/content/browser/accessibility/browser_accessibility_manager.cc
index 3c99ffca4f86774c733bddbc2aec98cc9b5ba0cc..cc8f660a7d79794ec52c620a5c5cbdf1e39b5126 100644
--- a/content/browser/accessibility/browser_accessibility_manager.cc
+++ b/content/browser/accessibility/browser_accessibility_manager.cc
@@ -399,6 +399,9 @@ void BrowserAccessibilityManager::OnNodeWillBeDeleted(ui::AXNode* node) {
 }
 
 void BrowserAccessibilityManager::OnSubtreeWillBeDeleted(ui::AXNode* node) {
+  BrowserAccessibility* obj = GetFromAXNode(node);
+  if (obj)
+    obj->OnSubtreeWillBeDeleted();
 }
 
 void BrowserAccessibilityManager::OnNodeCreated(ui::AXNode* node) {
@@ -413,9 +416,17 @@ void BrowserAccessibilityManager::OnNodeChanged(ui::AXNode* node) {
 }
 
 void BrowserAccessibilityManager::OnAtomicUpdateFinished(
-    bool root_changed, const std::vector<ui::AXTreeDelegate::Change>& changes) {
-  for (size_t i = 0; i < changes.size(); ++i)
-    GetFromAXNode(changes[i].node)->OnUpdateFinished();
+    bool root_changed,
+    const std::vector<ui::AXTreeDelegate::Change>& changes) {
+  for (size_t i = 0; i < changes.size(); ++i) {
+    BrowserAccessibility* obj = GetFromAXNode(changes[i].node);
+    if (!obj)
+      continue;
+
+    obj->OnUpdateFinished();
+    if (changes[i].type == AXTreeDelegate::SUBTREE_CREATED)
+      GetFromAXNode(changes[i].node)->OnSubtreeCreationFinished();
+  }
 }
 
 ui::AXTreeUpdate BrowserAccessibilityManager::SnapshotAXTreeForTesting() {