Fix Android black frames from MSE config changes.

media/filters/gpu_video_decoder.cc

 // 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.
 
 #include "media/filters/gpu_video_decoder.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 455 matching lines @@
   DVLOG(3) << "PictureReady()";
   DCheckGpuVideoAcceleratorFactoriesTaskRunnerIsCurrent();
 
   PictureBufferMap::iterator it =
       assigned_picture_buffers_.find(picture.picture_buffer_id());
   if (it == assigned_picture_buffers_.end()) {
     DLOG(ERROR) << "Missing picture buffer: " << picture.picture_buffer_id();
     NotifyError(VideoDecodeAccelerator::PLATFORM_FAILURE);
     return;
   }
-  const PictureBuffer& pb = it->second;
+  PictureBuffer& pb = it->second;
+  if (pb.size() != picture.visible_rect().size()) {

[liberato (no reviews please), 2016/03/02 16:50:36]

i don't think that you want to do this unconditionally.  the picture should have
a flag (like allow_overlay) that permits it.

it's not causing the current problem, of course.

[chcunningham, 2016/03/02 21:46:19]

Ack, happy to add a flag.

In our chat earlier I think we reached consensus that pb.size() !=
picture.visible_rect().size()... as visible rect is a slightly different concept
from pb size. In the case of AVDA, this visible rect is coming directly from the
size_ member, so perhaps its not a concern for AVDA... but I'm still feeling a
little unsure if copying size from visible rect -> pb size is semantically
correct for VDA's in general (even if guarded with a flag). WDYT?

+    // Update the PictureBuffer size to match that of the Picture. Some VDA's
+    // (e.g. Android) will handle resolution changes internally without
+    // requesting new PictureBuffers. Sending a Picture of unmatched size is
+    // the signal that we should update the size of our PictureBuffer.
+    LOG(ERROR) << __FUNCTION__ << " Updating size of PictureBuffer[" << pb.id()
+               << "]"
+               << " from:" << pb.size().ToString()
+               << " to:" << picture.visible_rect().size().ToString();
+    pb.set_size(picture.visible_rect().size());
+  }
 
   // Update frame's timestamp.
   base::TimeDelta timestamp;
   // Some of the VDAs like DXVA, AVDA, and VTVDA don't support and thus don't
   // provide us with visible size in picture.size, passing (0, 0) instead, so
   // for those cases drop it and use config information instead.
   gfx::Rect visible_rect;
   gfx::Size natural_size;
   GetBufferData(picture.bitstream_buffer_id(), &timestamp, &visible_rect,
                 &natural_size);
@@ skipping 218 matching lines @@
   }
   return false;
 }
 
 void GpuVideoDecoder::DCheckGpuVideoAcceleratorFactoriesTaskRunnerIsCurrent()
     const {
   DCHECK(factories_->GetTaskRunner()->BelongsToCurrentThread());
 }
 
 }  // namespace media