ImageCapture: Implement TakePhoto() for Linux/CrOs

media/capture/video/linux/v4l2_capture_delegate.h

Index: media/capture/video/linux/v4l2_capture_delegate.h
diff --git a/media/capture/video/linux/v4l2_capture_delegate.h b/media/capture/video/linux/v4l2_capture_delegate.h
index 120272745c9d2d690f44497a23c873d66c221adf..2ed379be80e5a51497f87860c57e8c40d1a1ef12 100644
--- a/media/capture/video/linux/v4l2_capture_delegate.h
+++ b/media/capture/video/linux/v4l2_capture_delegate.h
@@ -55,6 +55,8 @@ class V4L2CaptureDelegate final
                         std::unique_ptr<VideoCaptureDevice::Client> client);
   void StopAndDeAllocate();
 
+  void TakePhoto(VideoCaptureDevice::TakePhotoCallback callback);
+
   void SetRotation(int rotation);
 
  private:
@@ -67,6 +69,11 @@ class V4L2CaptureDelegate final
 
   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);
 
@@ -80,8 +87,9 @@ class V4L2CaptureDelegate final
   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_;