media: Implement MojoVideoDecoder::CanReadWithoutStalling().

media/mojo/clients/mojo_video_decoder.cc

 // Copyright 2016 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_video_decoder.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/callback_helpers.h"
 #include "base/location.h"
@@ skipping 92 matching lines @@
 
   uint64_t decode_id = decode_counter_++;
   pending_decodes_[decode_id] = decode_cb;
   remote_decoder_->Decode(std::move(mojo_buffer),
                           base::Bind(&MojoVideoDecoder::OnDecodeDone,
                                      base::Unretained(this), decode_id));
 }
 
 void MojoVideoDecoder::OnVideoFrameDecoded(
     const scoped_refptr<VideoFrame>& frame,
+    bool can_read_without_stalling,
     const base::Optional<base::UnguessableToken>& release_token) {
   DVLOG(2) << __func__;
   DCHECK(task_runner_->BelongsToCurrentThread());
 
+  // TODO(sandersd): Prove that all paths read this value again after running
+  // |output_cb_|. In practice this isn't very important, since all decoders
+  // running via MojoVideoDecoder currently use a static value.
+  can_read_without_stalling_ = can_read_without_stalling;
+
   if (release_token) {
     frame->SetReleaseMailboxCB(
         BindToCurrentLoop(base::Bind(&MojoVideoDecoder::OnReleaseMailbox,
                                      weak_this_, release_token.value())));
   }
   output_cb_.Run(frame);
 }
 
 void MojoVideoDecoder::OnReleaseMailbox(
     const base::UnguessableToken& release_token,
@@ skipping 38 matching lines @@
 }
 
 bool MojoVideoDecoder::NeedsBitstreamConversion() const {
   DVLOG(3) << __func__;
   DCHECK(initialized_);
   return needs_bitstream_conversion_;
 }
 
 bool MojoVideoDecoder::CanReadWithoutStalling() const {
   DVLOG(3) << __func__;
-  return true;
+  return can_read_without_stalling_;
 }
 
 int MojoVideoDecoder::GetMaxDecodeRequests() const {
   DVLOG(3) << __func__;
   DCHECK(initialized_);
   return max_decode_requests_;
 }
 
 void MojoVideoDecoder::BindRemoteDecoder() {
   DVLOG(3) << __func__;
@@ skipping 41 matching lines @@
 
   for (const auto& pending_decode : pending_decodes_)
     pending_decode.second.Run(DecodeStatus::DECODE_ERROR);
   pending_decodes_.clear();
 
   if (!reset_cb_.is_null())
     base::ResetAndReturn(&reset_cb_).Run();
 }
 
 }  // namespace media