Enable WebViewAccessiblityTest for OOPIF webview.

content/renderer/render_frame_impl.cc

Index: content/renderer/render_frame_impl.cc
diff --git a/content/renderer/render_frame_impl.cc b/content/renderer/render_frame_impl.cc
index 0d0b86ed03312d638868dc3fe4585d1cf84fe04e..5f9456d6bd88c02d9f846f7252f564faedae890f 100644
--- a/content/renderer/render_frame_impl.cc
+++ b/content/renderer/render_frame_impl.cc
@@ -2270,8 +2270,11 @@ void RenderFrameImpl::OnAdvanceFocus(blink::WebFocusType type,
                                      int32_t source_routing_id) {
   RenderFrameProxy* source_frame =
       RenderFrameProxy::FromRoutingID(source_routing_id);
-  if (!source_frame)
+  if (!source_frame) {
+    render_view_->webview()->SetInitialFocus(type ==
+                                             blink::kWebFocusTypeBackward);
     return;
+  }
 
   render_view_->webview()->AdvanceFocusAcrossFrames(
       type, source_frame->web_frame(), frame_);