Mojo framework for AndroidOverlay.

media/mojo/interfaces/android_overlay.mojom

+// Copyright 2017 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 media.mojom;
+
+import "media/mojo/interfaces/media_types.mojom";
+import "ui/gfx/geometry/mojo/geometry.mojom";
+
+interface AndroidOverlayProvider {
+  // Create an overlay and send it to |client|, using |config| as the initial
+  // configuration.  |client| will be notified when the overlay is ready.
+  CreateOverlay(AndroidOverlayClient client, AndroidOverlayConfig config);
+};
+
+// One overlay instance.
+interface AndroidOverlay {
+  // Cause a layout to occur later.
+  ScheduleLayout(gfx.mojom.Rect rect);
+};
+
+// Provided by the client to receive status updates about the overlay.
+interface AndroidOverlayClient {
+  // |overlay| is the AndroidOverlay that was created in response to a
+  // CreateOverlay request.
+  OnInitialized(AndroidOverlay overlay);

[dcheng, 2017/02/28 05:22:04]

Can we remove the need for this method by plumbing it through CreateOverlay as
well? AndroidOverlay& is useful for this purpose (it passes an interface request
which the other side will bind)

[liberato (no reviews please), 2017/03/06 07:51:05]

thanks, done!

+
+  // |surface_key| is the key that can be used to retrieve the surface via
+  // binder separately.
+  OnSurfaceReady(uint64 surface_key);
+
+  // Indicates that this overlay has been permanently destroyed.  This can
+  // happen before OnInitialized, or before OnSurfaceReady.  It will be the last
+  // callback from the overlay in any case.
+  OnDestroyed();
+};
+
+// This is not a mirror of AndroidOverlay::Config, since it contains things that
+// are specific to the mojo implementation.
+struct AndroidOverlayConfig {
+    uint32 render_frame_id;
+    uint32 renderer_pid;

[dcheng, 2017/02/28 05:22:04]

We shouldn't be passing render frame ID or the renderer PID over IPC, as we
can't trust the renderer.

[liberato (no reviews please), 2017/03/06 07:51:05]

this came up earlier.  this isn't exposed to the renderer; the gpu process will
be using it.  i'll dig up the thread with chrome-security, but TL;DR was "gpu
can do what it likes anyway. it can get the pid from the ipc channel, so the
renderer only sends the frame id.  it's allowed to lie about that, since the pid
is reliable.".

that said, i'd really like to remove both frame id and pid from here.  please
see my comments about the layering issue.

+
+    gfx.mojom.Rect rect;
+};