ImageCapture: Implement TakePhoto() for Linux/CrOs

media/capture/video/linux/v4l2_capture_delegate.h

 // 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.
 
 #ifndef MEDIA_CAPTURE_VIDEO_LINUX_V4L2_CAPTURE_DELEGATE_H_
 #define MEDIA_CAPTURE_VIDEO_LINUX_V4L2_CAPTURE_DELEGATE_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 37 matching lines @@
       const scoped_refptr<base::SingleThreadTaskRunner>& v4l2_task_runner,
       int power_line_frequency);
 
   // Forward-to versions of VideoCaptureDevice virtual methods.
   void AllocateAndStart(int width,
                         int height,
                         float frame_rate,
                         std::unique_ptr<VideoCaptureDevice::Client> client);
   void StopAndDeAllocate();
 
+  void TakePhoto(VideoCaptureDevice::TakePhotoCallback callback);
+
   void SetRotation(int rotation);
 
  private:
   friend class base::RefCountedThreadSafe<V4L2CaptureDelegate>;
   ~V4L2CaptureDelegate();
 
   // VIDIOC_QUERYBUFs a buffer from V4L2, creates a BufferTracker for it and
   // enqueues it (VIDIOC_QBUF) back into V4L2.
   bool MapAndQueueBuffer(int index);
 
   void DoCapture();
 
+  class BufferTracker;
+  mojom::BlobPtr GetPhotoBlob(
+      const scoped_refptr<BufferTracker>& buffer_tracker,
+      const uint32_t bytesused);
+
   void SetErrorState(const tracked_objects::Location& from_here,
                      const std::string& reason);
 
   const scoped_refptr<base::SingleThreadTaskRunner> v4l2_task_runner_;
   const VideoCaptureDeviceDescriptor device_descriptor_;
   const int power_line_frequency_;
 
   // The following members are only known on AllocateAndStart().
   VideoCaptureFormat capture_format_;
   v4l2_format video_fmt_;
   std::unique_ptr<VideoCaptureDevice::Client> client_;
   base::ScopedFD device_fd_;
 
+  std::queue<VideoCaptureDevice::TakePhotoCallback> take_photo_callbacks_;
+
   // Vector of BufferTracker to keep track of mmap()ed pointers and their use.
-  class BufferTracker;
   std::vector<scoped_refptr<BufferTracker>> buffer_tracker_pool_;
 
   bool is_capturing_;
   int timeout_count_;
 
   // Clockwise rotation in degrees. This value should be 0, 90, 180, or 270.
   int rotation_;
 
   DISALLOW_COPY_AND_ASSIGN(V4L2CaptureDelegate);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_CAPTURE_VIDEO_LINUX_V4L2_CAPTURE_DELEGATE_H_