Disable idle suspend for Chromecast

media/base/pipeline_impl.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/base/pipeline_impl.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 228 matching lines @@
 
 void PipelineImpl::SetCdm(CdmContext* cdm_context,
                           const CdmAttachedCB& cdm_attached_cb) {
   DCHECK(main_task_runner_->BelongsToCurrentThread());
 
   media_task_runner_->PostTask(
       FROM_HERE, base::Bind(&PipelineImpl::SetCdmTask, weak_this_, cdm_context,
                             cdm_attached_cb));
 }
 
+bool PipelineImpl::CanSuspend() const {
+  DCHECK(media_task_runner_->BelongsToCurrentThread());
+  DCHECK(renderer_);

[sandersd (OOO until July 31), 2016/05/23 18:41:58]

Since CanSuspend() can be called before Start(), and while suspended, there
should be a default return value when there is no |renderer_|. It should be safe
to always return true.

Another implementation option (and an overall cleaner one, in terms of removing
|pipeline_| from WMPI) is to handle that fallback in PipelineController, which
unlike PipelineImpl is spec'd to return meaningful values before Start().

Actually testing |renderer_| isn't thread safe though, the pointer gets changed
on the media thread. Additional locking may be required.

[alokp, 2016/05/23 20:32:01]

I am also working on a patch that moves the renderer_ field into an internal
class that runs on the media thread. This patch is supposed to eliminate all
locking and waitable events from PipelineImpl:
https://codereview.chromium.org/1999893004/

+  return renderer_->AllowSuspend();
+}
+
 void PipelineImpl::SetErrorForTesting(PipelineStatus status) {
   OnError(status);
 }
 
 bool PipelineImpl::HasWeakPtrsForTesting() const {
   DCHECK(media_task_runner_->BelongsToCurrentThread());
   return weak_factory_.HasWeakPtrs();
 }
 
 void PipelineImpl::SetState(State next_state) {
@@ skipping 680 matching lines @@
 void PipelineImpl::BufferingStateChanged(BufferingState new_buffering_state) {
   DVLOG(1) << __FUNCTION__ << "(" << new_buffering_state << ") ";
   DCHECK(media_task_runner_->BelongsToCurrentThread());
 
   main_task_runner_->PostTask(
       FROM_HERE, base::Bind(&Pipeline::Client::OnBufferingStateChange,
                             weak_client_, new_buffering_state));
 }
 
 }  // namespace media