V4L2VideoDecodeAccelerator: implement flush by VIDIOC_DECODER_CMD.

media/gpu/v4l2_device.h

Index: media/gpu/v4l2_device.h
diff --git a/media/gpu/v4l2_device.h b/media/gpu/v4l2_device.h
index edf4686543080995a1ccdeb442f210010b165afc..e9f22df582fd2b009483dcb729b45e181d8fba30 100644
--- a/media/gpu/v4l2_device.h
+++ b/media/gpu/v4l2_device.h
@@ -24,10 +24,10 @@
 #include "ui/gl/gl_bindings.h"
 
 // TODO(posciak): remove this once V4L2 headers are updated.
-#define V4L2_PIX_FMT_VP9 v4l2_fourcc('V', 'P', '9', '0')
-#define V4L2_PIX_FMT_H264_SLICE v4l2_fourcc('S', '2', '6', '4')
-#define V4L2_PIX_FMT_VP8_FRAME v4l2_fourcc('V', 'P', '8', 'F')
 #define V4L2_PIX_FMT_MT21 v4l2_fourcc('M', 'T', '2', '1')
+#ifndef V4L2_BUF_FLAG_LAST
+#define V4L2_BUF_FLAG_LAST 0x00100000
+#endif
 
 namespace media {