media: Support SetCdm() on VideoDecodeAccelerator interface.

media/video/video_decode_accelerator.h

 // Copyright (c) 2012 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_VIDEO_VIDEO_DECODE_ACCELERATOR_H_
 #define MEDIA_VIDEO_VIDEO_DECODE_ACCELERATOR_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 65 matching lines @@
     // Callback to notify that decoded has decoded the end of the current
     // bitstream buffer.
     virtual void NotifyEndOfBitstreamBuffer(int32 bitstream_buffer_id) = 0;
 
     // Flush completion callback.
     virtual void NotifyFlushDone() = 0;
 
     // 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.
     virtual void NotifyError(Error error) = 0;
 
    protected:
     virtual ~Client() {}
   };
 
   // Video decoder functions.
@@ skipping 39 matching lines @@
   // back to the client, followed by NotifyFlushDone() being called on the
   // client.  Can be used to implement "end of stream" notification.
   virtual void Flush() = 0;
 
   // Resets the decoder: all pending inputs are dropped immediately and the
   // decoder returned to a state ready for further Decode()s, followed by
   // NotifyResetDone() being called on the client.  Can be used to implement
   // "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
   // no more callbacks will be made on the client.  Deletes |this|
   // unconditionally, so make sure to drop all pointers to it!
   virtual void Destroy() = 0;
 
   // GPU PROCESS ONLY.  Implementations of this interface in the
   // content/common/gpu/media should implement this, and implementations in
   // other processes should not override the default implementation.
@@ skipping 26 matching lines @@
 // uses "Destroy()" instead of trying to use the destructor.
 template <>
 struct MEDIA_EXPORT DefaultDeleter<media::VideoDecodeAccelerator> {
  public:
   void operator()(void* video_decode_accelerator) const;
 };
 
 }  // namespace base
 
 #endif  // MEDIA_VIDEO_VIDEO_DECODE_ACCELERATOR_H_