Force a GuestView's embedder to be focused on TouchStart.

content/browser/frame_host/render_widget_host_view_guest.cc

Index: content/browser/frame_host/render_widget_host_view_guest.cc
diff --git a/content/browser/frame_host/render_widget_host_view_guest.cc b/content/browser/frame_host/render_widget_host_view_guest.cc
index 95dd9efd9653c5a0a1395fec55da725d199b7700..ea3aefd2829f60d9f4e6ad41eea90daf43647490 100644
--- a/content/browser/frame_host/render_widget_host_view_guest.cc
+++ b/content/browser/frame_host/render_widget_host_view_guest.cc
@@ -647,6 +647,11 @@ void RenderWidgetHostViewGuest::OnHandleInputEvent(
   }
 
   if (blink::WebInputEvent::isTouchEventType(event->type)) {
+    if (event->type == blink::WebInputEvent::TouchStart &&
+        !embedder->GetView()->HasFocus()) {
+      embedder->GetView()->Focus();
+    }
+
     host_->ForwardTouchEventWithLatencyInfo(
         *static_cast<const blink::WebTouchEvent*>(event),
         ui::LatencyInfo());