Motown: Framework parts for mojo transport (producer/consumer/mediapipe) and control (audiotrack).

services/media/framework/engine.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 "services/media/framework/engine.h"
 
 namespace mojo {
 namespace media {
 
 Engine::Engine() {}
@@ skipping 21 matching lines @@
       [] (const InputRef& input,
           const OutputRef& output,
           const Stage::UpstreamCallback& callback) {
         DCHECK(input.actual().prepared());
         input.stage_->UnprepareInput(input.index_);
         output.stage_->UnprepareOutput(output.index_, callback);
       });
 }
 
 void Engine::FlushOutput(const OutputRef& output) {
+  if (!output.connected()) {
+    return;
+  }
   VisitDownstream(
       output,
       [] (const OutputRef& output,
           const InputRef& input,
           const Stage::DownstreamCallback& callback) {
         DCHECK(input.actual().prepared());
         output.stage_->FlushOutput(output.index_);
         input.stage_->FlushInput(input.index_, callback);
       });
 }
@@ skipping 136 matching lines @@
 
   Stage* stage = demand_backlog_.top();
   demand_backlog_.pop();
   DCHECK(stage->in_demand_backlog_);
   stage->in_demand_backlog_ = false;
   return stage;
 }
 
 }  // namespace media
 }  // namespace mojo