V4L2SVDA/VAAPIVDA: use visible size from decoder and pass to client

media/gpu/h264_decoder.cc

Index: media/gpu/h264_decoder.cc
diff --git a/media/gpu/h264_decoder.cc b/media/gpu/h264_decoder.cc
index aed9658374805c9854aaf4c0fa76dc34e67a5412..d5b0aee8f0928bb020abfb149693301370500b33 100644
--- a/media/gpu/h264_decoder.cc
+++ b/media/gpu/h264_decoder.cc
@@ -177,6 +177,8 @@ bool H264Decoder::InitCurrPicture(const H264SliceHeader* slice_hdr) {
            sizeof(curr_pic_->ref_pic_marking));
   }
 
+  curr_pic_->visible_rect = visible_rect_;
+
   return true;
 }
 
@@ -1124,6 +1126,12 @@ bool H264Decoder::ProcessSPS(int sps_id, bool* need_new_buffers) {
     dpb_.set_max_num_pics(max_dpb_size);
   }
 
+  gfx::Rect new_visible_rect = sps->GetVisibleRect().value_or(gfx::Rect());
+  if (visible_rect_ != new_visible_rect) {
+    DVLOG(2) << "New visible rect: " << new_visible_rect.ToString();
+    visible_rect_ = new_visible_rect;
+  }
+
   if (!UpdateMaxNumReorderFrames(sps))
     return false;
   DVLOG(1) << "max_num_reorder_frames: " << max_num_reorder_frames_;