[Mojo Video Capture] Retire buffers when Android Chromium goes to the background

media/capture/video/video_capture_device_client.h

Index: media/capture/video/video_capture_device_client.h
diff --git a/media/capture/video/video_capture_device_client.h b/media/capture/video/video_capture_device_client.h
index b2dcb0a15b188d6364b2e9142ee3bab264ac2b58..a7a8d0cdf30f8a5d4d2c374ceb3dc3ef8318f9de 100644
--- a/media/capture/video/video_capture_device_client.h
+++ b/media/capture/video/video_capture_device_client.h
@@ -9,10 +9,12 @@
 #include <stdint.h>
 
 #include <memory>
+#include <set>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
+#include "base/threading/thread_collision_warner.h"
 #include "media/capture/capture_export.h"
 #include "media/capture/video/video_capture_device.h"
 
@@ -103,6 +105,7 @@ class CAPTURE_EXPORT VideoCaptureDeviceClient
 
   // The receiver to which we post events.
   const std::unique_ptr<VideoFrameReceiver> receiver_;
+  std::set<int> buffer_ids_known_by_receiver_;
 
   const VideoCaptureJpegDecoderFactoryCB jpeg_decoder_factory_callback_;
   std::unique_ptr<VideoCaptureJpegDecoder> external_jpeg_decoder_;
@@ -123,6 +126,11 @@ class CAPTURE_EXPORT VideoCaptureDeviceClient
 
   media::VideoPixelFormat last_captured_pixel_format_;
 
+  // Thread collision warner to ensure that producer-facing API is not called
+  // concurrently. Producers are allowed to call from multiple threads, but not
+  // concurrently.
+  DFAKE_MUTEX(call_from_producer_);

[mcasas, 2017/01/20 22:41:32]

Ooooh this is brilliant!

[chfremer, 2017/01/25 23:45:23]

Acknowledged.

+
   DISALLOW_COPY_AND_ASSIGN(VideoCaptureDeviceClient);
 };