Preserve page-level focus for subframe cross-process navigations.

content/browser/frame_host/render_frame_host_manager.cc

Index: content/browser/frame_host/render_frame_host_manager.cc
diff --git a/content/browser/frame_host/render_frame_host_manager.cc b/content/browser/frame_host/render_frame_host_manager.cc
index b43007f59010a209e0f3d84f22dc2f27e67b5a41..f6df60a22e696651294ee4c957537060ba2b09c3 100644
--- a/content/browser/frame_host/render_frame_host_manager.cc
+++ b/content/browser/frame_host/render_frame_host_manager.cc
@@ -2215,7 +2215,14 @@ void RenderFrameHostManager::CommitPending() {
   if (will_focus_location_bar) {
     delegate_->SetFocusToLocationBar(false);
   } else if (focus_render_view && render_frame_host_->GetView()) {
-    render_frame_host_->GetView()->Focus();
+    if (is_main_frame) {
+      render_frame_host_->GetView()->Focus();
+    } else {
+      // The main frame's view is already focused, but we need to set
+      // page-level focus in the subframe's renderer.
+      frame_tree_node_->frame_tree()->SetPageFocus(
+          render_frame_host_->GetSiteInstance(), true);
+    }
   }
 
   // Notify that we've swapped RenderFrameHosts. We do this before shutting down