Fix Android black frames from MSE config changes.

media/filters/gpu_video_decoder.cc

Index: media/filters/gpu_video_decoder.cc
diff --git a/media/filters/gpu_video_decoder.cc b/media/filters/gpu_video_decoder.cc
index 6801aafc069ad2dd60c66a573d2e7f4977b47e2e..e1a77e8ef8a8e8bd939605cb92f4eefc01c7b885 100644
--- a/media/filters/gpu_video_decoder.cc
+++ b/media/filters/gpu_video_decoder.cc
@@ -473,7 +473,18 @@ void GpuVideoDecoder::PictureReady(const media::Picture& picture) {
     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;