Automatically fire AX events on Win based on tree changes

content/browser/accessibility/browser_accessibility_manager.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.h"
 
 #include <stddef.h>
 #include <utility>
 
 #include "base/logging.h"
@@ skipping 416 matching lines @@
     const AXEventNotificationDetails& detail = details[index];
 
     // Find the node corresponding to the id that's the target of the
     // event (which may not be the root of the update tree).
     ui::AXNode* node = tree_->GetFromId(detail.id);
     if (!node)
       continue;
 
     ui::AXEvent event_type = detail.event_type;
 
-#if defined(OS_MACOSX)
-    if (event_type != ui::AX_EVENT_HOVER)
+// On Mac and Windows, nearly all events are now fired implicitly,
+// so we should ignore most events from the renderer.
+#if defined(OS_MACOSX) || defined(OS_WIN)
+    if (event_type != ui::AX_EVENT_HOVER &&
+        event_type != ui::AX_EVENT_LOCATION_CHANGED &&
+        event_type != ui::AX_EVENT_SCROLLED_TO_ANCHOR) {
       continue;
+    }
 #endif  // !defined(OS_MACOSX)
 
     if (event_type == ui::AX_EVENT_FOCUS ||
         event_type == ui::AX_EVENT_BLUR) {
       if (osk_state_ != OSK_DISALLOWED_BECAUSE_TAB_HIDDEN &&
           osk_state_ != OSK_DISALLOWED_BECAUSE_TAB_JUST_APPEARED) {
         osk_state_ = OSK_ALLOWED;
       }
 
       // We already handled all focus events above.
@@ skipping 862 matching lines @@
       hit_test_result = parent;
     parent = parent->PlatformGetParent();
   }
 
   last_hover_ax_tree_id_ = hit_test_result->manager()->ax_tree_id();
   last_hover_node_id_ = hit_test_result->GetId();
   last_hover_bounds_ = hit_test_result->GetScreenBoundsRect();
 }
 
 }  // namespace content