Implement GpuArcVideoService for arc video accelerator

content/browser/gpu/gpu_arc_video_service_host.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/browser/gpu/gpu_arc_video_service_host.h"
+
+#include "base/location.h"
+#include "base/logging.h"
+#include "base/message_loop/message_loop.h"
+#include "content/browser/gpu/gpu_process_host.h"
+#include "content/common/gpu/gpu_messages.h"
+#include "ipc/ipc_message_macros.h"
+#include "ipc/ipc_message_utils.h"
+
+namespace content {
+
+namespace {
+void CreateChannelOnIOThread(
+    const GpuProcessHost::CreateArcVideoAcceleratorChannelCallback& callback) {
+  GpuProcessHost* gpu_process_host =
+      GpuProcessHost::Get(GpuProcessHost::GPU_PROCESS_KIND_SANDBOXED,
+                          CAUSE_FOR_GPU_LAUNCH_ARCVIDEOACCELERATOR);
+  gpu_process_host->CreateArcVideoAcceleratorChannel(callback);
+}
+}
+
+GpuArcVideoServiceHost::GpuArcVideoServiceHost(
+    const scoped_refptr<base::SingleThreadTaskRunner>& io_task_runner)
+    : io_task_runner_(io_task_runner),
+      num_pending_request_(0),
+      weak_factory_(this) {}
+
+GpuArcVideoServiceHost::~GpuArcVideoServiceHost() {
+  DCHECK(CalledOnValidThread());
+
+  arc::ArcBridgeService* bridge_service = arc::ArcBridgeService::Get();
+  if (bridge_service) {
+    while (num_pending_request_ > 0)
+      NotifyArcAcceleratorChannelCreated(IPC::ChannelHandle());
+    bridge_service->RemoveObserver(this);
+    bridge_service->RemoveVideoServiceObserver(this);
+  }
+}
+
+void GpuArcVideoServiceHost::Initialize() {
+  DCHECK(CalledOnValidThread());
+
+  arc::ArcBridgeService* bridge_service = arc::ArcBridgeService::Get();
+  DCHECK(bridge_service);

[Pawel Osciak, 2015/12/16 10:17:58]

Should we actually if(bridge_service) here (and in l.91)? In destructor we if(),
but here we only DCHECK?

[kcwu, 2015/12/16 14:05:33]

Basically it is bug if bridge_service is null, hence the DCHECK.

I usually treat dtor as special case -- I prefer do-nothing-object (merely
created and destroyed but no methods called) don't crash. This may be helpful
for writing tests. Does it make sense?

+  bridge_service->AddObserver(this);
+  bridge_service->AddVideoServiceObserver(this);
+}
+
+void GpuArcVideoServiceHost::OnStateChanged(
+    arc::ArcBridgeService::State state) {
+  DCHECK(CalledOnValidThread());
+  switch (state) {
+    case arc::ArcBridgeService::State::STOPPING:
+      Shutdown();
+      break;
+    default:
+      break;
+  }
+}
+
+void GpuArcVideoServiceHost::OnRequestArcVideoAcceleratorChannel() {
+  DCHECK(CalledOnValidThread());
+  num_pending_request_++;
+  io_task_runner_->PostTask(
+      FROM_HERE,
+      base::Bind(
+          &CreateChannelOnIOThread,
+          base::Bind(
+              &GpuArcVideoServiceHost::NotifyArcAcceleratorChannelCreated,
+              weak_factory_.GetWeakPtr())));
+}
+
+void GpuArcVideoServiceHost::Shutdown() {
+  GpuProcessHost::SendOnIO(GpuProcessHost::GPU_PROCESS_KIND_SANDBOXED,
+                           CAUSE_FOR_GPU_LAUNCH_NO_LAUNCH,
+                           new GpuMsg_ShutdownArcVideoService());
+}
+
+void GpuArcVideoServiceHost::NotifyArcAcceleratorChannelCreated(
+    const IPC::ChannelHandle& handle) {
+  DCHECK(CalledOnValidThread());
+
+  DCHECK_GT(num_pending_request_, 0);
+
+  arc::ArcBridgeService* bridge_service = arc::ArcBridgeService::Get();
+  DCHECK(bridge_service);
+  num_pending_request_--;
+  ignore_result(bridge_service->NotifyVideoAcceleratorChannelCreated(handle));

[Pawel Osciak, 2015/12/16 10:17:58]

Is there any other caller that doesn't ignore_result? If not, should we just
make it void?

[kcwu, 2015/12/16 14:05:33]

Done.

+}
+
+}  // namespace content