media: Create Mojo StructTraits for VideoFrame

media/mojo/clients/mojo_decryptor.cc

 // Copyright 2015 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.
 
 #include "media/mojo/clients/mojo_decryptor.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <utility>
@@ skipping 206 matching lines @@
 
   Decryptor::AudioFrames audio_frames;
   for (size_t i = 0; i < audio_buffers.size(); ++i)
     audio_frames.push_back(audio_buffers[i].To<scoped_refptr<AudioBuffer>>());
 
   audio_decode_cb.Run(status, audio_frames);
 }
 
 void MojoDecryptor::OnVideoDecoded(const VideoDecodeCB& video_decode_cb,
                                    Status status,
-                                   mojom::VideoFramePtr video_frame,
+                                   const scoped_refptr<VideoFrame>& video_frame,

[dcheng, 2017/06/05 20:33:01]

Nit: Consider passing by value and using std::move() to transfer the refcount
around.

[sandersd (OOO until July 31), 2017/06/05 20:46:13]

This would be the ideal setup, but I don't see a combination of attributes that
results in the intended signatures in the generated mojo bindings.

                                    mojom::FrameResourceReleaserPtr releaser) {
   DVLOG_IF(1, status != kSuccess) << __func__ << "(" << status << ")";
   DVLOG_IF(3, status == kSuccess) << __func__;
   DCHECK(thread_checker_.CalledOnValidThread());
 
-  if (video_frame.is_null()) {
-    video_decode_cb.Run(status, nullptr);
-    return;
-  }
-
-  scoped_refptr<VideoFrame> frame(video_frame.To<scoped_refptr<VideoFrame>>());
-
   // If using shared memory, ensure that |releaser| is closed when
   // |frame| is destroyed.
-  if (releaser) {
-    frame->AddDestructionObserver(
+  if (video_frame && releaser) {
+    video_frame->AddDestructionObserver(
         base::Bind(&ReleaseFrameResource, base::Passed(&releaser)));
   }
 
-  video_decode_cb.Run(status, frame);
+  video_decode_cb.Run(status, video_frame);
 }
 
 }  // namespace media