Fix WebView accessibility

content/browser/frame_host/render_frame_host_impl.cc

Index: content/browser/frame_host/render_frame_host_impl.cc
diff --git a/content/browser/frame_host/render_frame_host_impl.cc b/content/browser/frame_host/render_frame_host_impl.cc
index 5c47a5e73341b62b98a43d514dd642f74ffa96aa..8a9ae7b8fca5122f638c0f226b3d2a80b7d4070d 100644
--- a/content/browser/frame_host/render_frame_host_impl.cc
+++ b/content/browser/frame_host/render_frame_host_impl.cc
@@ -205,6 +205,7 @@ RenderFrameHostImpl::RenderFrameHostImpl(SiteInstance* site_instance,
       nav_entry_id_(0),
       accessibility_reset_token_(0),
       accessibility_reset_count_(0),
+      browser_plugin_embedder_ax_tree_id_(AXTreeIDRegistry::kNoAXTreeID),
       no_create_browser_accessibility_manager_for_testing_(false),
       web_ui_type_(WebUI::kNoWebUI),
       pending_web_ui_type_(WebUI::kNoWebUI),
@@ -2407,6 +2408,11 @@ void RenderFrameHostImpl::UpdateAXTreeData() {
   delegate_->AccessibilityEventReceived(details);
 }
 
+void RenderFrameHostImpl::SetBrowserPluginEmbedderAXTreeID(
+    AXTreeIDRegistry::AXTreeID ax_tree_id) {
+  browser_plugin_embedder_ax_tree_id_ = ax_tree_id;
+}
+
 void RenderFrameHostImpl::SetTextTrackSettings(
     const FrameMsg_TextTrackSettings_Params& params) {
   DCHECK(!GetParent());
@@ -2638,11 +2644,13 @@ AXTreeIDRegistry::AXTreeID RenderFrameHostImpl::RoutingIDToAXTreeID(
 AXTreeIDRegistry::AXTreeID
 RenderFrameHostImpl::BrowserPluginInstanceIDToAXTreeID(
     int instance_id) {
-  RenderFrameHost* guest = delegate()->GetGuestByInstanceID(
-      this, instance_id);
+  RenderFrameHostImpl* guest = static_cast<RenderFrameHostImpl*>(
+      delegate()->GetGuestByInstanceID(this, instance_id));
   if (!guest)
     return AXTreeIDRegistry::kNoAXTreeID;
 
+  guest->SetBrowserPluginEmbedderAXTreeID(GetAXTreeID());
+
   return guest->GetAXTreeID();
 }
 
@@ -2687,6 +2695,9 @@ void RenderFrameHostImpl::AXContentTreeDataToAXTreeData(
   if (src.parent_routing_id != -1)
     dst->parent_tree_id = RoutingIDToAXTreeID(src.parent_routing_id);
 
+  if (browser_plugin_embedder_ax_tree_id_ != AXTreeIDRegistry::kNoAXTreeID)
+    dst->parent_tree_id = browser_plugin_embedder_ax_tree_id_;
+
   // If this is not the root frame tree node, we're done.
   if (frame_tree_node()->parent())
     return;