[Mojo Video Capture] Adapt video_capture service to refactored video capture stack

services/video_capture/device_media_to_mojo_adapter.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 "services/video_capture/device_media_to_mojo_adapter.h"
 
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "media/capture/video/video_capture_buffer_pool_impl.h"
 #include "media/capture/video/video_capture_buffer_tracker_factory_impl.h"
 #include "media/capture/video/video_capture_jpeg_decoder.h"
 #include "services/video_capture/receiver_mojo_to_media_adapter.h"
 
+namespace {
+
+// The maximum number of video frame buffers in-flight at any one time.
+// If all buffers are still in use by consumers when new frames are produced
+// those frames get dropped.
+static const int kMaxBufferCount = 3;
+}
+
 namespace video_capture {
 
 DeviceMediaToMojoAdapter::DeviceMediaToMojoAdapter(
     std::unique_ptr<media::VideoCaptureDevice> device,
     const media::VideoCaptureJpegDecoderFactoryCB&
         jpeg_decoder_factory_callback)
     : device_(std::move(device)),
       jpeg_decoder_factory_callback_(jpeg_decoder_factory_callback),
       device_running_(false) {}
 
 DeviceMediaToMojoAdapter::~DeviceMediaToMojoAdapter() {
-  Stop();
+  if (device_running_)
+    device_->StopAndDeAllocate();
 }
 
 void DeviceMediaToMojoAdapter::Start(
     const media::VideoCaptureParams& requested_settings,
     mojom::ReceiverPtr receiver) {
   receiver.set_connection_error_handler(
       base::Bind(&DeviceMediaToMojoAdapter::OnClientConnectionErrorOrClose,
                  base::Unretained(this)));
 
   auto media_receiver =
       base::MakeUnique<ReceiverMojoToMediaAdapter>(std::move(receiver));
 
   // Create a dedicated buffer pool for the device usage session.
-  const int kMaxBufferCount = 2;
   auto buffer_tracker_factory =
       base::MakeUnique<media::VideoCaptureBufferTrackerFactoryImpl>();
   scoped_refptr<media::VideoCaptureBufferPool> buffer_pool(
       new media::VideoCaptureBufferPoolImpl(std::move(buffer_tracker_factory),
-                                            kMaxBufferCount));
+                                            max_buffer_pool_buffer_count()));
 
   auto device_client = base::MakeUnique<media::VideoCaptureDeviceClient>(
       std::move(media_receiver), buffer_pool, jpeg_decoder_factory_callback_);
 
   device_->AllocateAndStart(requested_settings, std::move(device_client));
   device_running_ = true;
 }
 
+void DeviceMediaToMojoAdapter::OnReceiverReportingUtilization(
+    int32_t frame_feedback_id,
+    double utilization) {
+  device_->OnUtilizationReport(frame_feedback_id, utilization);
+}
+
 void DeviceMediaToMojoAdapter::Stop() {
   if (device_running_ == false)
     return;
+  device_running_ = false;
   device_->StopAndDeAllocate();
-  device_running_ = false;
 }
 
 void DeviceMediaToMojoAdapter::OnClientConnectionErrorOrClose() {
   Stop();
 }
 
+// static
+int DeviceMediaToMojoAdapter::max_buffer_pool_buffer_count() {
+  return kMaxBufferCount;
+}
+
 }  // namespace video_capture