Don't require VDAs to return all PictureBuffers at once.

content/common/gpu/media/android_deferred_rendering_backing_strategy.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 "content/common/gpu/media/android_deferred_rendering_backing_strategy.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "content/common/gpu/gpu_channel.h"
 #include "content/common/gpu/media/avda_codec_image.h"
 #include "content/common/gpu/media/avda_return_on_failure.h"
 #include "content/common/gpu/media/avda_shared_state.h"
 #include "gpu/command_buffer/service/texture_manager.h"
 #include "ui/gl/android/surface_texture.h"
 #include "ui/gl/gl_bindings.h"
 
 namespace content {
 
-// TODO(liberato): This is an entirely made-up number.  It depends on how
-// many decoded buffers that the MediaCodec is willing to have outstanding
-// at any one time.  Only one is guaranteed.  crbug.com/531606.
-enum { kNumPictureBuffers = 3 };
+// This is the maximum number of pictures that we will allow to be outstanding
+// at once.  We might not be able to support this many in all circumstances,
+// depending on how many decoded buffers the MediaCodec is willing to
+// give us.  Only one is guaranteed.  However, we also indicate in our
+// capabilities that we make no guarantees about it, so this is okay.
+enum { kNumPictureBuffers = 4 };

[DaleCurtis, 2015/12/04 18:40:13]

Should this be limits:kMaxFrames + 1 like in the copy back strategy?

[liberato (no reviews please), 2015/12/04 18:50:04]

done, and removed GetNumPictureBuffers.

 
 AndroidDeferredRenderingBackingStrategy::
     AndroidDeferredRenderingBackingStrategy()
     : state_provider_(nullptr), media_codec_(nullptr) {}
 
 AndroidDeferredRenderingBackingStrategy::
     ~AndroidDeferredRenderingBackingStrategy() {}
 
 void AndroidDeferredRenderingBackingStrategy::Initialize(
     AVDAStateProvider* state_provider) {
@@ skipping 152 matching lines @@
   // doesn't know about them.
   media_codec_ = codec;
   for (const std::pair<int, media::PictureBuffer>& entry : buffers) {
     AVDACodecImage* avImage = GetImageForPicture(entry.second);
     avImage->SetMediaCodec(codec);
     avImage->SetMediaCodecBufferIndex(-1);
   }
 }
 
 }  // namespace content