<webview>: Make contentWindow available prior to attachment (on display:none).

extensions/browser/guest_view/guest_view_message_filter.cc

Index: extensions/browser/guest_view/guest_view_message_filter.cc
diff --git a/extensions/browser/guest_view/guest_view_message_filter.cc b/extensions/browser/guest_view/guest_view_message_filter.cc
index 04c711f74173b61ccfc318dd907833ca37900183..52f8d6bc9297fd127c4e7d774737bd938e5adcb7 100644
--- a/extensions/browser/guest_view/guest_view_message_filter.cc
+++ b/extensions/browser/guest_view/guest_view_message_filter.cc
@@ -40,8 +40,6 @@ void GuestViewMessageFilter::OverrideThreadForMessage(
   switch (message.type()) {
     case GuestViewHostMsg_AttachGuest::ID:
     case GuestViewHostMsg_CreateMimeHandlerViewGuest::ID:
-      *thread = BrowserThread::UI;
-      break;
     case GuestViewHostMsg_ResizeGuest::ID:
       *thread = BrowserThread::UI;
       break;