Mus+Ash: propagate Surface ID to parents

services/ui/public/interfaces/window_tree.mojom

Index: services/ui/public/interfaces/window_tree.mojom
diff --git a/services/ui/public/interfaces/window_tree.mojom b/services/ui/public/interfaces/window_tree.mojom
index c7f68eda14f6938d4804c58036ace972879bbf10..865097bb1fd2388b4931355d9018fc1216369213 100644
--- a/services/ui/public/interfaces/window_tree.mojom
+++ b/services/ui/public/interfaces/window_tree.mojom
@@ -5,6 +5,7 @@
 module ui.mojom;
 
 import "cc/ipc/surface_id.mojom";
+import "cc/ipc/surface_sequence.mojom";
 import "services/ui/public/interfaces/cursor.mojom";
 import "services/ui/public/interfaces/event_matcher.mojom";
 import "services/ui/public/interfaces/mus_constants.mojom";
@@ -142,6 +143,9 @@ interface WindowTree {
                 Surface& surface,
                 SurfaceClient client);
 
+  // Returns surface reference back to window server for reclamation.
+  ReturnSurfaceReference(uint32 window_id, cc.mojom.SurfaceSequence sequence);
+
   // Reparents a window.
   // This fails for any of the following reasons:
   // . |parent| or |child| does not identify a valid window.
@@ -421,6 +425,13 @@ interface WindowTreeClient {
 
   OnWindowPredefinedCursorChanged(uint32 window_id, Cursor cursor_id);
 
+  // Invoked when a client window submits a new surface ID.

[rjkroege, 2016/10/12 18:21:16]

per our discussion: in the long term, the client should give the surface id
directly to the embedder yes? So this is temporary yes?

[Fady Samuel, 2016/10/12 18:22:57]

Yes, until we figure out all the details of a direct connection.

+  OnWindowSurfaceCreated(uint32 window_id,
+                         cc.mojom.SurfaceId surface_id,
+                         cc.mojom.SurfaceSequence surface_sequence,
+                         gfx.mojom.Size frame_size,
+                         float device_scale_factor);
+                         
   // Called when the mouse cursor enters a window on this connection for the
   // first time, providing a list of available mime types. We want to send this
   // set of data only one time, so this isn't part of OnDragEnter(), which