[Mojo Video Capture] Stop service when last client disconnects.

media/capture/video/video_capture_device_client.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 "media/capture/video/video_capture_device_client.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 133 matching lines @@
 
   if (last_captured_pixel_format_ != format.pixel_format) {
     OnLog("Pixel format: " +
           media::VideoPixelFormatToString(format.pixel_format));
     last_captured_pixel_format_ = format.pixel_format;
 
     if (format.pixel_format == media::PIXEL_FORMAT_MJPEG &&
         !external_jpeg_decoder_initialized_) {
       external_jpeg_decoder_initialized_ = true;
       external_jpeg_decoder_ = jpeg_decoder_factory_callback_.Run();
-      external_jpeg_decoder_->Initialize();
+      if (external_jpeg_decoder_)
+        external_jpeg_decoder_->Initialize();
     }
   }
 
   if (!format.IsValid())
     return;
 
   if (format.pixel_format == media::PIXEL_FORMAT_Y16) {
     return OnIncomingCapturedY16Data(data, length, format, reference_time,
                                      timestamp, frame_feedback_id);
   }
@@ skipping 311 matching lines @@
   auto buffer_access = buffer.handle_provider->GetHandleForInProcessAccess();
   memcpy(buffer_access->data(), data, length);
   const VideoCaptureFormat output_format =
       VideoCaptureFormat(format.frame_size, format.frame_rate,
                          media::PIXEL_FORMAT_Y16, media::PIXEL_STORAGE_CPU);
   OnIncomingCapturedBuffer(std::move(buffer), output_format, reference_time,
                            timestamp);
 }
 
 }  // namespace media