Allow MimeHandlerViewGuest be embedded inside OOPIFs

components/guest_view/browser/guest_view_manager.h

Index: components/guest_view/browser/guest_view_manager.h
diff --git a/components/guest_view/browser/guest_view_manager.h b/components/guest_view/browser/guest_view_manager.h
index 033e2a2cd1bc044412f85871708345a1728f757e..29d1474ddd8b00505835a6412b0d69f19f3267d1 100644
--- a/components/guest_view/browser/guest_view_manager.h
+++ b/components/guest_view/browser/guest_view_manager.h
@@ -62,9 +62,9 @@ class GuestViewManager : public content::BrowserPluginGuestManager,
       int guest_instance_id,
       int embedder_render_process_id);
 
-  // Associates the Browser Plugin with |element_instance_id| to a
-  // guest that has ID of |guest_instance_id| and sets initialization
-  // parameters, |params| for it.
+  // Associates the Browser Plugin with |element_instance_id| to a guest that
+  // has ID of |guest_instance_id| and sets initialization parameters, |params|
+  // for it.
   void AttachGuest(int embedder_process_id,
                    int element_instance_id,
                    int guest_instance_id,
@@ -266,6 +266,12 @@ class GuestViewManager : public content::BrowserPluginGuestManager,
   using CallbacksForEachEmbedderID = std::map<int, CallbacksForEachViewID>;
   CallbacksForEachEmbedderID view_destruction_callback_map_;
 
+  // The routing ID of the embedder which most recently sent an attach request.
+  // We use this value to later identify the RenderFrameHost and WebContents
+  // which embed the guest. This is mainly used for MimeHandlerViewGuest and
+  // specifically when the guest is embedded inside a cross origin frame.
+  int attaching_guest_embedder_routing_id_;

[wjmaclean, 2016/10/20 14:47:22]

Where is this used?

[EhsanK, 2016/10/20 21:41:17]

Stale. Thanks!

+
   // This is used to ensure that an EmbedderRenderProcessHostObserver will not
   // call into this GuestViewManager after it has been destroyed.
   base::WeakPtrFactory<GuestViewManager> weak_ptr_factory_;