Add AndroidVideoSurfaceChooser to manage overlays.

media/gpu/avda_overlay_helper.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_AVDA_OVERLAY_HELPER_H_
+#define MEDIA_GPU_AVDA_OVERLAY_HELPER_H_
+
+#include "base/bind.h"
+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "media/base/android/android_overlay.h"
+#include "media/base/android/android_overlay_factory.h"
+#include "media/gpu/media_gpu_export.h"
+
+namespace media {
+
+// Manage details of which overlay to use for video playback, if any.
+class MEDIA_GPU_EXPORT AVDAOverlayHelper {
+ public:
+  // Notify the client that |overlay| is ready for use.  The client may get
+  // the surface immediatly.

[tguilbert, 2017/04/21 22:55:46]

s/immediatly/immediately

[liberato (no reviews please), 2017/04/27 18:30:12]

Done.

+  using UseOverlayCB =
+      base::Callback<void(std::unique_ptr<AndroidOverlay> overlay)>;
+
+  // Notify the client that the most recently provided overlay should be
+  // discarded.  The overlay is still valid, but we recommend against
+  // using it soon, in favor of a SurfaceTexture.
+  // TODO(liberato): document the differences between this an 'Immediately'

[tguilbert, 2017/04/21 22:55:46]

s/an/and

[liberato (no reviews please), 2017/04/27 18:30:12]

Done.

+  using UseSurfaceTextureCB = base::Callback<void(void)>;
+
+  // Callback that mirrors AndroidOverlay::DestroyedCB .  The surface
+  // that was provided with |overlay| is being destroyed.
+  using StopUsingOverlayImmediatelyCB = base::Callback<void(AndroidOverlay*)>;
+
+  AVDAOverlayHelper() {}
+  virtual ~AVDAOverlayHelper() {}
+
+  // Notify us that our client is ready for overlays.  We will send it a
+  // callback telling it whether to start with a SurfaceTexture or overlay,
+  // either synchronously or post one very soon.
+  virtual void Startup(

[watk, 2017/04/22 00:29:07]

nit: startup is a noun. Start() or Initialize()? I prefer Initialize().

[liberato (no reviews please), 2017/04/27 18:30:12]

Done, Initialize.

+      const UseOverlayCB& use_overlay_cb,
+      const UseSurfaceTextureCB& use_surface_texture_cb,
+      const StopUsingOverlayImmediatelyCB& stop_immediately_cb,
+      std::unique_ptr<AndroidOverlayFactory> initial_factory) = 0;
+
+  // Notify us that a new factory has arrived.  May be null to indicate that
+  // WMPI has revoked the most recent factory.
+  virtual void OnOverlayFactory(
+      std::unique_ptr<AndroidOverlayFactory> factory) = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(AVDAOverlayHelper);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_GPU_AVDA_OVERLAY_HELPER_H_