[Mojo Video Capture] Implement a VideoCaptureProvider that uses the video capture service

content/browser/renderer_host/media/mojo_service_video_capture_device_launcher.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 "content/browser/renderer_host/media/mojo_service_video_capture_device_launcher.h"
+
+#include "content/browser/renderer_host/media/mojo_service_launched_video_capture_device.h"
+#include "content/public/browser/browser_thread.h"
+#include "media/capture/video/video_frame_receiver_on_task_runner.h"
+#include "mojo/public/cpp/bindings/strong_binding.h"
+#include "services/video_capture/public/cpp/receiver_media_to_mojo_adapter.h"
+
+namespace content {
+
+MojoServiceVideoCaptureDeviceLauncher::MojoServiceVideoCaptureDeviceLauncher(
+    video_capture::mojom::DeviceFactoryPtr* device_factory)
+    : device_factory_(device_factory), state_(State::READY_TO_LAUNCH) {}
+
+MojoServiceVideoCaptureDeviceLauncher::
+    ~MojoServiceVideoCaptureDeviceLauncher() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK(state_ == State::READY_TO_LAUNCH);
+}
+
+void MojoServiceVideoCaptureDeviceLauncher::LaunchDeviceAsync(
+    const std::string& device_id,
+    MediaStreamType stream_type,
+    const media::VideoCaptureParams& params,
+    base::WeakPtr<media::VideoFrameReceiver> receiver,
+    Callbacks* callbacks,
+    base::OnceClosure done_cb) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK(state_ == State::READY_TO_LAUNCH);
+
+  if (stream_type != content::MEDIA_DEVICE_VIDEO_CAPTURE) {
+    // This launcher only supports MEDIA_DEVICE_VIDEO_CAPTURE.
+    NOTREACHED();
+    return;
+  }
+
+  if (!device_factory_->is_bound()) {
+    // This can happen when the MojoServiceVideoCaptureProvider owning
+    // |device_factory_| loses connection to the service process and resets
+    // |device_factory_|.
+    OnDeviceCreationFailed(callbacks, std::move(done_cb));
+    return;
+  }
+  video_capture::mojom::DevicePtr device;
+  (*device_factory_)
+      ->CreateDevice(
+          device_id, mojo::MakeRequest(&device),
+          base::Bind(
+              &MojoServiceVideoCaptureDeviceLauncher::OnCreateDeviceCallback,
+              base::Unretained(this), params, base::Passed(&device),
+              std::move(receiver), callbacks, base::Passed(&done_cb)));
+  state_ = State::DEVICE_START_IN_PROGRESS;
+}
+
+void MojoServiceVideoCaptureDeviceLauncher::AbortLaunch() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  if (state_ == State::DEVICE_START_IN_PROGRESS)
+    state_ = State::DEVICE_START_ABORTING;
+}
+
+void MojoServiceVideoCaptureDeviceLauncher::OnCreateDeviceCallback(
+    const media::VideoCaptureParams& params,
+    video_capture::mojom::DevicePtr device,
+    base::WeakPtr<media::VideoFrameReceiver> receiver,
+    Callbacks* callbacks,
+    base::OnceClosure done_cb,
+    video_capture::mojom::DeviceAccessResultCode result_code) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  switch (result_code) {
+    case video_capture::mojom::DeviceAccessResultCode::SUCCESS:
+      OnDeviceCreatedSuccessfully(params, std::move(device),
+                                  std::move(receiver), callbacks,
+                                  std::move(done_cb));
+      return;
+    case video_capture::mojom::DeviceAccessResultCode::ERROR_DEVICE_NOT_FOUND:
+    case video_capture::mojom::DeviceAccessResultCode::NOT_INITIALIZED:
+      OnDeviceCreationFailed(callbacks, std::move(done_cb));
+      return;
+  }
+}
+
+void MojoServiceVideoCaptureDeviceLauncher::OnDeviceCreatedSuccessfully(
+    const media::VideoCaptureParams& params,
+    video_capture::mojom::DevicePtr device,
+    base::WeakPtr<media::VideoFrameReceiver> receiver,
+    Callbacks* callbacks,
+    base::OnceClosure done_cb) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  if (state_ == State::DEVICE_START_ABORTING) {
+    device.reset();
+    callbacks->OnDeviceLaunchAborted();
+    base::ResetAndReturn(&done_cb).Run();
+    return;
+  }
+
+  auto receiver_adapter =
+      base::MakeUnique<video_capture::ReceiverMediaToMojoAdapter>(
+          base::MakeUnique<media::VideoFrameReceiverOnTaskRunner>(
+              std::move(receiver),
+              BrowserThread::GetTaskRunnerForThread(BrowserThread::IO)));
+  video_capture::mojom::ReceiverPtr receiver_proxy;
+  mojo::MakeStrongBinding<video_capture::mojom::Receiver>(
+      std::move(receiver_adapter), mojo::MakeRequest(&receiver_proxy));
+  device->Start(params, std::move(receiver_proxy));
+  callbacks->OnDeviceLaunched(
+      base::MakeUnique<MojoServiceLaunchedVideoCaptureDevice>(
+          std::move(device)));
+  base::ResetAndReturn(&done_cb).Run();
+}
+
+void MojoServiceVideoCaptureDeviceLauncher::OnDeviceCreationFailed(
+    Callbacks* callbacks,
+    base::OnceClosure done_cb) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  if (state_ == State::DEVICE_START_ABORTING)
+    callbacks->OnDeviceLaunchAborted();
+  else
+    callbacks->OnDeviceLaunchFailed();
+  base::ResetAndReturn(&done_cb).Run();
+}
+
+}  // namespace content