V4L2VideoDecodeAccelerator: support external buffer import

media/gpu/v4l2_image_processor.h

Index: media/gpu/v4l2_image_processor.h
diff --git a/media/gpu/v4l2_image_processor.h b/media/gpu/v4l2_image_processor.h
index 337face0127547a47fd00281817a0a30b76a26d5..bbebe8d01670bc4d8dd791e1e89ab9f29c8364d1 100644
--- a/media/gpu/v4l2_image_processor.h
+++ b/media/gpu/v4l2_image_processor.h
@@ -41,6 +41,7 @@ class MEDIA_GPU_EXPORT V4L2ImageProcessor {
   bool Initialize(VideoPixelFormat input_format,
                   VideoPixelFormat output_format,
                   v4l2_memory input_memory_type,
+                  v4l2_memory output_memory_type,
                   gfx::Size input_visible_size,
                   gfx::Size input_allocated_size,
                   gfx::Size output_visible_size,
@@ -84,9 +85,13 @@ class MEDIA_GPU_EXPORT V4L2ImageProcessor {
   // Called by client to process |frame|. The resulting processed frame will be
   // stored in |output_buffer_index| output buffer and notified via |cb|. The
   // processor will drop all its references to |frame| after it finishes
-  // accessing it.
-  void Process(const scoped_refptr<VideoFrame>& frame,
+  // accessing it. If |output_memory_type_| is V4L2_MEMORY_DMABUF, the caller
+  // should pass non-empty |output_dmabuf_fds| and the processed frame will be
+  // stored in those buffers. If the number of |output_dmabuf_fds| is not
+  // expected, this function will return false.
+  bool Process(const scoped_refptr<VideoFrame>& frame,
                int output_buffer_index,
+               std::vector<base::ScopedFD> output_dmabuf_fds,
                const FrameReadyCB& cb);
 
   // Reset all processing frames. After this method returns, no more callbacks
@@ -110,19 +115,26 @@ class MEDIA_GPU_EXPORT V4L2ImageProcessor {
   // Record for output buffers.
   struct OutputRecord {
     OutputRecord();
+    OutputRecord(OutputRecord&&) = default;
     ~OutputRecord();
     bool at_device;
+    // The processed frame will be stored in these buffers if
+    // |output_memory_type_| is V4L2_MEMORY_DMABUF
+    std::vector<base::ScopedFD> dmabuf_fds;
   };
 
   // Job record. Jobs are processed in a FIFO order. This is separate from
   // InputRecord, because an InputRecord may be returned before we dequeue
   // the corresponding output buffer. The processed frame will be stored in
-  // |output_buffer_index| output buffer.
+  // |output_buffer_index| output buffer. If |output_memory_type_| is
+  // V4L2_MEMORY_DMABUF, the processed frame will be stored in
+  // |output_dmabuf_fds|.
   struct JobRecord {
     JobRecord();
     ~JobRecord();
     scoped_refptr<VideoFrame> frame;
     int output_buffer_index;
+    std::vector<base::ScopedFD> output_dmabuf_fds;
     FrameReadyCB ready_cb;
   };
 
@@ -164,6 +176,7 @@ class MEDIA_GPU_EXPORT V4L2ImageProcessor {
   VideoPixelFormat input_format_;
   VideoPixelFormat output_format_;
   v4l2_memory input_memory_type_;
+  v4l2_memory output_memory_type_;
   uint32_t input_format_fourcc_;
   uint32_t output_format_fourcc_;