gl: Add YVU_420 support to GLImageOzoneNativePixmap.

ui/ozone/platform/drm/gpu/gbm_buffer.cc

Index: ui/ozone/platform/drm/gpu/gbm_buffer.cc
diff --git a/ui/ozone/platform/drm/gpu/gbm_buffer.cc b/ui/ozone/platform/drm/gpu/gbm_buffer.cc
index 30e208b408f0e4a3d21b51aeafc471bdffcdb33e..66c917931a144c4548085d2560e31d07f97cf55f 100644
--- a/ui/ozone/platform/drm/gpu/gbm_buffer.cc
+++ b/ui/ozone/platform/drm/gpu/gbm_buffer.cc
@@ -58,6 +58,10 @@ bool GbmBuffer::AreFdsValid() const {
   return true;
 }
 
+size_t GbmBuffer::GetFdNum() const {
+  return fds_.size();
+}
+
 int GbmBuffer::GetFd(size_t plane) const {
   DCHECK_LT(plane, fds_.size());
   return fds_[plane].get();
@@ -184,6 +188,10 @@ bool GbmPixmap::AreDmaBufFdsValid() const {
   return buffer_->AreFdsValid();
 }
 
+size_t GbmPixmap::GetDmaBufFdNum() const {
+  return buffer_->GetFdNum();
+}
+
 int GbmPixmap::GetDmaBufFd(size_t plane) const {
   return buffer_->GetFd(plane);
 }