media: Support SetCdm() on VideoDecodeAccelerator interface.

media/video/video_decode_accelerator.h

Index: media/video/video_decode_accelerator.h
diff --git a/media/video/video_decode_accelerator.h b/media/video/video_decode_accelerator.h
index 2b71d65ab075926a56d690856d7de1b95a595406..fe23031e88ad871b423178212322e8e3560a1497 100644
--- a/media/video/video_decode_accelerator.h
+++ b/media/video/video_decode_accelerator.h
@@ -83,6 +83,9 @@ class MEDIA_EXPORT VideoDecodeAccelerator {
     // Reset completion callback.
     virtual void NotifyResetDone() = 0;
 
+    // SetCdm completion callback.

[liberato (no reviews please), 2015/11/11 23:29:10]

might want to describe default behavior, here and SetCdm.

[xhwang, 2015/11/13 01:16:55]

Done.

+    virtual void NotifyCdmSet(bool success);
+
     // Callback to notify about decoding errors. Note that errors in
     // Initialize() will not be reported here, but will instead be indicated by
     // a false return value there.
@@ -142,6 +145,10 @@ class MEDIA_EXPORT VideoDecodeAccelerator {
   // "seek".
   virtual void Reset() = 0;
 
+  // Sets a CDM to be used by the video decoder to handle encrypted buffers,
+  // followed by Client::NotifyCdmSet() being called with the setting result.

[liberato (no reviews please), 2015/11/11 23:29:10]

right now, AVDA::Initialize, which is called very early, configures the codec
without a cdm.  to add one later, we'll have to destroy the codec, or defer
initialization.  how do you plan on handling this?

also, is it okay to call this at any time, or are there restrictions (e.g.
before the first call to Decode())?

[xhwang, 2015/11/13 01:16:55]

As discussed offline, there's no way to finish codec configuration synchronously
(Initialize is sync) on Android when EME is involved. So Initialize will return
immediately, but the real initialization will be delayed until the SetCdm(). The
real initialization result is returned in NotifyCdmAttached() call.

Updated the comments to clarify these.

+  virtual void SetCdm(int cdm_id);
+
   // Destroys the decoder: all pending inputs are dropped immediately and the
   // component is freed.  This call may asynchornously free system resources,
   // but its client-visible effects are synchronous.  After this method returns