Add multiple destruction callbacks to AndroidOverlay.

media/base/android/android_overlay.h

Index: media/base/android/android_overlay.h
diff --git a/media/base/android/android_overlay.h b/media/base/android/android_overlay.h
index 8b500a85d04a9961034ee43e3234489e55db6c89..4c1cad64869107a2b4ae93d83da95340f1bb8289 100644
--- a/media/base/android/android_overlay.h
+++ b/media/base/android/android_overlay.h
@@ -5,9 +5,12 @@
 #ifndef MEDIA_BASE_ANDROID_ANDROID_OVERLAY_H_
 #define MEDIA_BASE_ANDROID_ANDROID_OVERLAY_H_
 
+#include <list>
+
 #include "base/android/scoped_java_ref.h"
 #include "base/callback.h"
 #include "base/macros.h"
+#include "base/memory/weak_ptr.h"
 #include "media/base/android_overlay_config.h"
 #include "media/base/media_export.h"
 #include "ui/gfx/geometry/rect.h"
@@ -37,7 +40,7 @@ namespace media {
 // AndroidOverlay isn't technically supposed to do that.
 class MEDIA_EXPORT AndroidOverlay {
  public:
-  virtual ~AndroidOverlay() {}
+  virtual ~AndroidOverlay();
 
   // Schedules a relayout of this overlay.  If called before the client is
   // notified that the surface is created, then the call will be ignored.
@@ -46,8 +49,18 @@ class MEDIA_EXPORT AndroidOverlay {
   // May be called during / after ReadyCB and before DestroyedCB.
   virtual const base::android::JavaRef<jobject>& GetJavaSurface() const = 0;
 
+  // Add a destruction callback that will be called if the surface is destroyed.
+  // These will be called in the same order that they're added.
+  void AddDestructionCallback(AndroidOverlayConfig::DestroyedCB cb);

[watk, 2017/05/16 19:10:29]

Destruction makes it sound a lot like you're registering for AndroidOverlay's
destructor.

What about AddOverlayDestroyedCb()

[tguilbert, 2017/05/16 19:11:51]

Can you document the guarantees of the contract? It seems as though there is no
guarantee the callbacks will actually be called back, if |this| is destroyed
during RunDestructionCallbacks().

[liberato (no reviews please), 2017/05/16 20:04:02]

there is a guarantee that it won't be called if |this| is destroyed by an
earlier callback.  i've updated the docs to make this clear.

[liberato (no reviews please), 2017/05/16 20:04:02]

AddSurfaceDestroyedCb()?

+
  protected:
-  AndroidOverlay() {}
+  AndroidOverlay();
+
+  void RunDestructionCallbacks();
+
+  std::list<AndroidOverlayConfig::DestroyedCB> destruction_cbs_;
+
+  base::WeakPtrFactory<AndroidOverlay> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(AndroidOverlay);
 };