Workaround for undeclared identifier V4L2_PIX_FMT_INVZ.

media/capture/video/linux/v4l2_capture_delegate.cc

Index: media/capture/video/linux/v4l2_capture_delegate.cc
diff --git a/media/capture/video/linux/v4l2_capture_delegate.cc b/media/capture/video/linux/v4l2_capture_delegate.cc
index 87068547c926ab0910724ea51d75e871a5cd5e71..096e0f1f542000d2125da2d64b29847e5d07d51b 100644
--- a/media/capture/video/linux/v4l2_capture_delegate.cc
+++ b/media/capture/video/linux/v4l2_capture_delegate.cc
@@ -23,6 +23,12 @@
 #if LINUX_VERSION_CODE < KERNEL_VERSION(4, 6, 0)
 // 16 bit depth, Realsense F200.
 #define V4L2_PIX_FMT_Z16 v4l2_fourcc('Z', '1', '6', ' ')
+#endif
+
+// TODO(aleksandar.stojiljkovic): Wrap this with kernel version check once the
+// format is introduced to kernel.
+// See https://crbug.com/661877
+#ifndef V4L2_PIX_FMT_INVZ
 // 16 bit depth, Realsense SR300.
 #define V4L2_PIX_FMT_INVZ v4l2_fourcc('I', 'N', 'V', 'Z')
 #endif