H264Decoder: Handle gaps in frame_num.

content/common/gpu/media/vaapi_video_decode_accelerator.cc

Index: content/common/gpu/media/vaapi_video_decode_accelerator.cc
diff --git a/content/common/gpu/media/vaapi_video_decode_accelerator.cc b/content/common/gpu/media/vaapi_video_decode_accelerator.cc
index 8af5b794b02c16667fabf55eb7a3a6e0e36e9e74..d5f0698ae1fae9b679832795af307f8248d36f1e 100644
--- a/content/common/gpu/media/vaapi_video_decode_accelerator.cc
+++ b/content/common/gpu/media/vaapi_video_decode_accelerator.cc
@@ -1232,10 +1232,15 @@ VaapiVideoDecodeAccelerator::VaapiH264Accelerator::
 void VaapiVideoDecodeAccelerator::VaapiH264Accelerator::FillVAPicture(
     VAPictureH264* va_pic,
     scoped_refptr<H264Picture> pic) {
-  scoped_refptr<VaapiDecodeSurface> dec_surface =
-      H264PictureToVaapiDecodeSurface(pic);
+  VASurfaceID va_surface_id = VA_INVALID_SURFACE;
+
+  if (!pic->nonexisting) {
+    scoped_refptr<VaapiDecodeSurface> dec_surface =
+        H264PictureToVaapiDecodeSurface(pic);
+    va_surface_id = dec_surface->va_surface()->id();
+  }
 
-  va_pic->picture_id = dec_surface->va_surface()->id();
+  va_pic->picture_id = va_surface_id;
   va_pic->frame_idx = pic->frame_num;
   va_pic->flags = 0;