[Mojo Video Capture] Implement a VideoCaptureProvider using the Mojo service (part 2)

content/browser/renderer_host/media/in_process_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/in_process_video_capture_device_launcher.h"
 
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/stringprintf.h"
 #include "content/browser/media/capture/desktop_capture_device_uma_types.h"
 #include "content/browser/media/capture/web_contents_video_capture_device.h"
@@ skipping 64 matching lines @@
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   DCHECK(state_ == State::READY_TO_LAUNCH);
 
   const int max_buffers =
       (stream_type == MEDIA_TAB_VIDEO_CAPTURE ? kMaxNumberOfBuffersForTabCapture
                                               : kMaxNumberOfBuffers);
 
   auto device_client = CreateDeviceClient(max_buffers, std::move(receiver));
 
   base::Closure start_capture_closure;
-  // Use of |this| is safe, because |done_cb| guarantees that |this|
+  // Use of Unretained |this| is safe, because |done_cb| guarantees that |this|
   // stays alive.
   ReceiveDeviceCallback after_start_capture_callback = media::BindToCurrentLoop(
       base::Bind(&InProcessVideoCaptureDeviceLauncher::OnDeviceStarted,
                  base::Unretained(this), callbacks, base::Passed(&done_cb)));
 
   switch (stream_type) {
     case MEDIA_DEVICE_VIDEO_CAPTURE: {
       start_capture_closure =
           base::Bind(&InProcessVideoCaptureDeviceLauncher::
                          DoStartDeviceCaptureOnDeviceThread,
@@ skipping 181 matching lines @@
   if (!video_capture_device) {
     result_callback.Run(nullptr);
     return;
   }
 
   video_capture_device->AllocateAndStart(params, std::move(device_client));
   result_callback.Run(std::move(video_capture_device));
 }
 
 }  // namespace content