[Mojo Video Capture] Create abstraction VideoCaptureProvider

content/browser/renderer_host/media/in_process_video_capture_provider.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 "content/browser/renderer_host/media/in_process_video_capture_provider.h"
+
+#include "content/browser/renderer_host/media/in_process_buildable_video_capture_device.h"
+
+namespace content {
+
+InProcessVideoCaptureProvider::InProcessVideoCaptureProvider(
+    std::unique_ptr<media::VideoCaptureSystem> video_capture_system,
+    scoped_refptr<base::SingleThreadTaskRunner> device_task_runner)
+    : video_capture_system_(std::move(video_capture_system)),
+      device_task_runner_(std::move(device_task_runner)) {}
+
+InProcessVideoCaptureProvider::~InProcessVideoCaptureProvider() = default;
+
+void InProcessVideoCaptureProvider::GetDeviceInfosAsync(
+    const base::Callback<void(
+        const std::vector<media::VideoCaptureDeviceInfo>&)>& result_callback) {
+  // Using Unretained() is safe because |this| owns |video_capture_system_| and
+  // |result_callback| has ownership of |this|.
+  device_task_runner_->PostTask(
+      FROM_HERE, base::Bind(&media::VideoCaptureSystem::GetDeviceInfosAsync,
+                            base::Unretained(video_capture_system_.get()),
+                            result_callback));
+}
+
+std::unique_ptr<BuildableVideoCaptureDevice>
+InProcessVideoCaptureProvider::CreateBuildableDevice(
+    const std::string& device_id,
+    MediaStreamType stream_type) {
+  return base::MakeUnique<InProcessBuildableVideoCaptureDevice>(
+      device_task_runner_, video_capture_system_.get());
+}
+
+}  // namespace content