Added a class acting as a fake caret for accessibility.

content/browser/accessibility/browser_accessibility_manager_win.cc

Index: content/browser/accessibility/browser_accessibility_manager_win.cc
diff --git a/content/browser/accessibility/browser_accessibility_manager_win.cc b/content/browser/accessibility/browser_accessibility_manager_win.cc
index 6e572695b654a8335058d1b9ba95f0e0b3371842..88d8dfe7b6f4398ea25afa885172bbd692087915 100644
--- a/content/browser/accessibility/browser_accessibility_manager_win.cc
+++ b/content/browser/accessibility/browser_accessibility_manager_win.cc
@@ -204,8 +204,12 @@ BrowserAccessibilityEvent::Result
   // 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 = -target->unique_id();
-  ::NotifyWinEvent(win_event_type, hwnd, OBJID_CLIENT, child_id);
+  if (event_type == ui::AX_EVENT_DOCUMENT_SELECTION_CHANGED) {
+    // We also need to fire an older MSAA event used by some assistive software.
+    ::NotifyWinEvent(EVENT_OBJECT_LOCATIONCHANGE, hwnd, OBJID_CARET, child_id);

[dmazzoni, 2017/04/17 05:07:34]

I don't think we want this here, because this means Windows Magnifier
won't work because it doesn't enable accessibility. I suggest calling this in
RenderWidgetHostViewBase::OnSelectionBoundsChanged instead.

+  }
 
+  ::NotifyWinEvent(win_event_type, hwnd, OBJID_CLIENT, child_id);
   return BrowserAccessibilityEvent::Sent;
 }