ImageCapture: queue requests if device is not started (Linux,CrOs)

media/capture/video/linux/video_capture_device_linux.h

 // Copyright (c) 2012 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.
 
 // Linux specific implementation of VideoCaptureDevice.
 // V4L2 is used for capturing. V4L2 does not provide its own thread for
 // capturing so this implementation uses a Chromium thread for fetching frames
 // from V4L2.
 
 #ifndef MEDIA_CAPTURE_VIDEO_LINUX_VIDEO_CAPTURE_DEVICE_LINUX_H_
@@ skipping 37 matching lines @@
   void SetRotation(int rotation);
 
  private:
   static int TranslatePowerLineFrequencyToV4L2(PowerLineFrequency frequency);
 
   // Internal delegate doing the actual capture setting, buffer allocation and
   // circulation with the V4L2 API. Created and deleted in the thread where
   // VideoCaptureDeviceLinux lives but otherwise operating on |v4l2_thread_|.
   scoped_refptr<V4L2CaptureDelegate> capture_impl_;
 
+  // Photo-related requests waiting for |v4l2_thread_| to be active.
+  std::list<base::Closure> photo_requests_queue_;
+
   base::Thread v4l2_thread_;  // Thread used for reading data from the device.
 
   const VideoCaptureDeviceDescriptor device_descriptor_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(VideoCaptureDeviceLinux);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_CAPTURE_VIDEO_LINUX_VIDEO_CAPTURE_DEVICE_LINUX_H_