Add AndroidVideoSurfaceChooser to manage overlays.

media/gpu/content_video_view_overlay_factory.h

+// 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.
+
+#ifndef MEDIA_GPU_CONTENT_VIDEO_VIEW_OVERLAY_FACTORY_H_
+#define MEDIA_GPU_CONTENT_VIDEO_VIEW_OVERLAY_FACTORY_H_
+
+#include "media/base/android/android_overlay_factory.h"
+
+namespace media {
+
+// Factory for CVV-based overlays.  One needs this only to hide the factory
+// impl from AVDA.
+class ContentVideoViewOverlayFactory : public AndroidOverlayFactory {

[watk, 2017/05/02 21:00:01]

I may be missing something, but it looks like this can be replaced with a single
callback that we bind the surface_id into.

I see that you're observing its destruction in the tests. You could do that by
binding an object that you can observe into the callback. 

[liberato (no reviews please), 2017/05/02 21:50:05]

per offline discussion, this is an interesting idea.  i'm going to leave it out
of this cl since it would change other, unrelated things (mojo factory impl).

will give it more consideration and do a follow-up cl if i think it'll work.

+ public:
+  // |surface_id| must not be kNoSurfaceID.
+  ContentVideoViewOverlayFactory(int32_t surface_id);
+  ~ContentVideoViewOverlayFactory() override;
+
+  std::unique_ptr<AndroidOverlay> CreateOverlay(
+      const AndroidOverlay::Config& config) override;
+
+ private:
+  int32_t surface_id_;
+
+  DISALLOW_COPY_AND_ASSIGN(ContentVideoViewOverlayFactory);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_GPU_ANDROID_CONTENT_VIDEO_VIEW_OVERLAY_FACTORY_H_