Add/remove surface references via MojoCompositorFrameSink.

cc/ipc/display_compositor.mojom

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 module cc.mojom;
 
 import "cc/ipc/frame_sink_id.mojom";
 import "cc/ipc/mojo_compositor_frame_sink.mojom";
 import "cc/ipc/surface_id.mojom";
 import "cc/ipc/surface_sequence.mojom";
@@ skipping 11 matching lines @@
 // are fixed for a given client and are determined ahead of time. Thus, a client
 // will typically simply request a CompositorFrameSink from the display
 // compositor host which will forward the request to the display compositor.
 interface DisplayCompositor {
   CreateCompositorFrameSink(
       cc.mojom.FrameSinkId frame_sink_id,
       gpu.mojom.SurfaceHandle widget,
       cc.mojom.MojoCompositorFrameSink& compositor_frame_sink,
       cc.mojom.MojoCompositorFrameSinkPrivate& compositor_frame_sink_private,
       cc.mojom.MojoCompositorFrameSinkClient compositor_frame_sink_client);
-
-  // TODO(fsamuel): This surface reference API is temporary. Surface references
-  // should be bundled with CompositorFrames.
-  AddRootSurfaceReference(cc.mojom.SurfaceId child_id);
-  AddSurfaceReference(cc.mojom.SurfaceId parent_id,
-                      cc.mojom.SurfaceId child_id);
-  RemoveRootSurfaceReference(cc.mojom.SurfaceId child_id);
-  RemoveSurfaceReference(cc.mojom.SurfaceId parent_id,
-                         cc.mojom.SurfaceId child_id);
 };
 
 // The DisplayCompositorClient interface is implemented by the Display
 // Compositor Host, a stable, and privileged peer service to the display
 // compositor. The display compositor host is either the browser process in
 // Chrome or the window server process.
 interface DisplayCompositorClient {
+  // Called by the display compostor when it is created. Provides the top level
+  // root surface id that should reference display roots. This will always be
+  // the first message sent.
+  OnDisplayCompositorCreated(cc.mojom.SurfaceId root_surface_id);
+
   // Called by the display compositor immediately upon receiving a
   // CompositorFrame with a new SurfaceId for the first time.
   OnSurfaceCreated(cc.mojom.SurfaceId surface_id,
                    gfx.mojom.Size frame_size,
                    float device_scale_factor);
 };