Raise UIA event on document selection change for windows

Fire UIA selection changed event in browser_accessibility_manager_win.cc
when document selection is changed.

Bug: 1030731
Change-Id: Ibeb72db403222d1e5a9bef540fafc42b9e01b02d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1975693Reviewed-by: Ian Prest <iapres@microsoft.com>
Commit-Queue: Mansi Awasthi <maawas@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#728793}

content/browser/accessibility/browser_accessibility_manager_win.cc

@@ -130,7 +130,7 @@ void BrowserAccessibilityManagerWin::FireBlinkEvent(
       FireUiaTextContainerEvent(UIA_Text_TextChangedEventId, node);
       break;
     case ax::mojom::Event::kTextSelectionChanged:
-      FireUiaTextContainerEvent(UIA_Text_TextSelectionChangedEventId, node);
+      text_selection_changed_events_.insert(node);
       break;
     default:
       break;
@@ -211,8 +211,10 @@ void BrowserAccessibilityManagerWin::FireGeneratedEvent(
       // Fire the event on the object where the focus of the selection is.
       int32_t focus_id = ax_tree()->GetUnignoredSelection().focus_object_id;
       BrowserAccessibility* focus_object = GetFromID(focus_id);
-      if (focus_object && focus_object->HasVisibleCaretOrSelection())
+      if (focus_object && focus_object->HasVisibleCaretOrSelection()) {
         FireWinAccessibilityEvent(IA2_EVENT_TEXT_CARET_MOVED, focus_object);
+        text_selection_changed_events_.insert(node);
+      }
       break;
     }
     // aria-dropeffect is deprecated in WAI-ARIA 1.1.
@@ -771,6 +773,12 @@ void BrowserAccessibilityManagerWin::FinalizeAccessibilityEvents() {
   }
   aria_properties_events_.clear();
 
+  for (auto&& sel_event_node : text_selection_changed_events_) {
+    FireUiaTextContainerEvent(UIA_Text_TextSelectionChangedEventId,
+                              sel_event_node);
+  }
+  text_selection_changed_events_.clear();
+
   for (auto&& selected : selection_events_) {
     auto* container = selected.first;
     auto&& changes = selected.second;

content/browser/accessibility/browser_accessibility_manager_win.h

@@ -105,6 +105,13 @@ class CONTENT_EXPORT BrowserAccessibilityManagerWin
   // changes, so we only fire the event once for every node.
   std::unordered_set<BrowserAccessibility*> aria_properties_events_;
 
+  // Since there could be duplicate text selection changed events on a node
+  // raised from both FireBlinkEvent and FireGeneratedEvent, we use an unordered
+  // set here to keep track of the unique nodes that had
+  // UIA_Text_TextSelectionChangedEventId, so we only fire the event once for
+  // every node.
+  std::unordered_set<BrowserAccessibility*> text_selection_changed_events_;
+
   // When the ignored state changes for a node, we only want to fire the
   // events relevant to the ignored state change (e.g. show / hide).
   // This set keeps track of what nodes should suppress superfluous events.

content/test/data/accessibility/event/text-selection-changed-expected-uia-win.txt

 Text_TextSelectionChanged on role=document
 === Start Continuation ===
+Text_TextSelectionChanged on role=document
 Text_TextSelectionChanged on role=textbox, name=input
 === Start Continuation ===
+Text_TextSelectionChanged on role=document
 Text_TextSelectionChanged on role=textbox, name=textarea