media: add video capture device for ARC++ camera HAL v3

media/capture/video/chromeos/video_capture_device_factory_chromeos.cc

+// Copyright 2017 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/capture/video/chromeos/video_capture_device_factory_chromeos.h"
+
+#include "base/files/file_util.h"
+#include "media/capture/video/linux/video_capture_device_factory_linux.h"
+
+namespace media {
+
+VideoCaptureDeviceFactoryChromeOS::VideoCaptureDeviceFactoryChromeOS(
+    scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner)
+    : ui_task_runner_(ui_task_runner), module_thread_("CameraModuleThread") {}
+
+VideoCaptureDeviceFactoryChromeOS::~VideoCaptureDeviceFactoryChromeOS() {}
+
+bool VideoCaptureDeviceFactoryChromeOS::Init() {
+  if (!module_thread_.Start()) {
+    LOG(ERROR) << "Module thread failed to start";
+    return false;
+  }
+  camera_hal_delegate_ = new CameraHalDelegate(module_thread_.task_runner());
+  return camera_hal_delegate_->StartCameraModuleIpc();
+}
+
+std::unique_ptr<VideoCaptureDevice>
+VideoCaptureDeviceFactoryChromeOS::CreateDevice(
+    const VideoCaptureDeviceDescriptor& device_descriptor) {
+  DCHECK(thread_checker_.CalledOnValidThread());

[chfremer, 2017/05/24 23:36:43]

Not an issue introduced by this CL, but it feels weird to me how
|thread_checker_| is a protected member of the base class, that the base class
does not actually use. Because of it, as a reader, I have to go and first read
the implementation of the base class to understand that this thread checker does
not do anything in the base class itself. If you agree, could we clean this up?

And if we do, we should probably use the new SEQUENCE_CHECKER macros instead of
base::ThreadChecker, unless we really need thread-affinity.

[jcliang, 2017/05/25 14:23:48]

I agree it's a bit weird. Can we do the clean up in another CL because this CL
is already a huge one?

[chfremer, 2017/05/25 17:13:07]

Agreed.

+  return camera_hal_delegate_->CreateDevice(ui_task_runner_, device_descriptor);

[chfremer, 2017/05/24 23:36:43]

Nit: Should we DCHECK that Init() has been called before |camera_hal_delegate_|
is used?

[jcliang, 2017/05/25 14:23:48]

Done.

+}
+
+void VideoCaptureDeviceFactoryChromeOS::GetSupportedFormats(
+    const VideoCaptureDeviceDescriptor& device_descriptor,
+    VideoCaptureFormats* supported_formats) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  camera_hal_delegate_->GetSupportedFormats(device_descriptor,
+                                            supported_formats);
+}
+
+void VideoCaptureDeviceFactoryChromeOS::GetDeviceDescriptors(
+    VideoCaptureDeviceDescriptors* device_descriptors) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  camera_hal_delegate_->GetDeviceDescriptors(device_descriptors);
+}
+
+#if defined(OS_CHROMEOS)
+const base::FilePath kArcCamera3Service("/usr/bin/arc_camera3_service");
+
+// static
+VideoCaptureDeviceFactory*
+VideoCaptureDeviceFactory::CreateVideoCaptureDeviceFactory(
+    scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner) {
+  if (base::PathExists(kArcCamera3Service)) {
+    std::unique_ptr<VideoCaptureDeviceFactoryChromeOS> factory(

[chfremer, 2017/05/24 23:36:43]

Please use base::MakeUnique<> here

[jcliang, 2017/05/25 14:23:48]

Done.

+        new VideoCaptureDeviceFactoryChromeOS(ui_task_runner));
+    if (!factory->Init()) {
+      return nullptr;
+    }
+    return factory.release();
+  } else {
+    return new VideoCaptureDeviceFactoryLinux(ui_task_runner);
+  }
+}
+#endif
+
+}  // namespace media