[ MimeHandlerView ] Printing for full page only

This CL makes sure that Ctrl+P and other sources of print only work for
a full-page MimeHandlerView. This means MimeHandlerViewGuest will be
considered full page only if it is in a main frame.

Bug: 967950
Change-Id: I0bc359f56adf9475fd450c12359ab4fae7b539b0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1633631
Reviewed-by: James MacLean <wjmaclean@chromium.org>
Commit-Queue: Ehsan Karamad <ekaramad@chromium.org>
Cr-Commit-Position: refs/heads/master@{#664274}

extensions/browser/guest_view/mime_handler_view/mime_handler_view_embedder.cc

@@ -186,7 +186,8 @@ void MimeHandlerViewEmbedder::DidCreateMimeHandlerViewGuest(
   // Full page plugin refers to <iframe> or main frame navigations to a
   // MimeHandlerView resource. In such cases MHVG does not have a frame
   // container.
-  bool is_full_page = !guest_view->maybe_has_frame_container();
+  bool is_full_page = !guest_view->maybe_has_frame_container() &&
+                      !guest_view->GetEmbedderFrame()->GetParent();
   MimeHandlerViewAttachHelper::Get(embedder_frame_process_id)
       ->AttachToOuterWebContents(guest_view, embedder_frame_process_id,
                                  outer_contents_rfh, element_instance_id_,