Use IAccessible2 to detect screen reader in Win Aura

content/browser/accessibility/browser_accessibility_win.cc

Index: content/browser/accessibility/browser_accessibility_win.cc
diff --git a/content/browser/accessibility/browser_accessibility_win.cc b/content/browser/accessibility/browser_accessibility_win.cc
index b5c8fd3c90dc8afb51505f9e7751b25afded305f..df3263e845ddfb2cc82fe58cb5ce1b117d08bcda 100644
--- a/content/browser/accessibility/browser_accessibility_win.cc
+++ b/content/browser/accessibility/browser_accessibility_win.cc
@@ -15,6 +15,7 @@
 #include "base/win/scoped_comptr.h"
 #include "base/win/windows_version.h"
 #include "content/browser/accessibility/browser_accessibility_manager_win.h"
+#include "content/browser/accessibility/browser_accessibility_state_impl.h"
 #include "content/common/accessibility_messages.h"
 #include "content/public/common/content_client.h"
 #include "ui/base/accessibility/accessible_text_utils.h"
@@ -2651,6 +2652,12 @@ STDMETHODIMP BrowserAccessibilityWin::QueryService(REFGUID guidService,
   if (!instance_active_)
     return E_FAIL;
 
+  // The system uses IAccessible APIs for many purposes, but only
+  // assistive technology like screen readers uses IAccessible2.
+  // Enable full accessibility support when IAccessible2 APIs are queried.
+  if (riid == IID_IAccessible2)
+    BrowserAccessibilityStateImpl::GetInstance()->EnableAccessibility();
+
   if (guidService == GUID_IAccessibleContentDocument) {
     // Special Mozilla extension: return the accessible for the root document.
     // Screen readers use this to distinguish between a document loaded event