libvpx: Pull from upstream

source/libvpx/webmdec.cc

Index: source/libvpx/webmdec.cc
diff --git a/source/libvpx/webmdec.cc b/source/libvpx/webmdec.cc
index d591f3e3d7413f9b12b9f609eb31c79e958a95f8..e152f5ee03a7275cabd0d7453cf5b4a1fa26ca31 100644
--- a/source/libvpx/webmdec.cc
+++ b/source/libvpx/webmdec.cc
@@ -63,6 +63,7 @@ int file_is_webm(struct WebmInputContext *webm_ctx,
                  struct VpxInputContext *vpx_ctx) {
   mkvparser::MkvReader *const reader = new mkvparser::MkvReader(vpx_ctx->file);
   webm_ctx->reader = reader;
+  webm_ctx->reached_eos = 0;
 
   mkvparser::EBMLHeader header;
   long long pos = 0;
@@ -121,6 +122,11 @@ int webm_read_frame(struct WebmInputContext *webm_ctx,
                     uint8_t **buffer,
                     size_t *bytes_in_buffer,
                     size_t *buffer_size) {
+  // This check is needed for frame parallel decoding, in which case this
+  // function could be called even after it has reached end of input stream.
+  if (webm_ctx->reached_eos) {
+    return 1;
+  }
   mkvparser::Segment *const segment =
       reinterpret_cast<mkvparser::Segment*>(webm_ctx->segment);
   const mkvparser::Cluster* cluster =
@@ -140,6 +146,7 @@ int webm_read_frame(struct WebmInputContext *webm_ctx,
       cluster = segment->GetNext(cluster);
       if (cluster == NULL || cluster->EOS()) {
         *bytes_in_buffer = 0;
+        webm_ctx->reached_eos = 1;
         return 1;
       }
       status = cluster->GetFirst(block_entry);
@@ -212,6 +219,7 @@ int webm_guess_framerate(struct WebmInputContext *webm_ctx,
   webm_ctx->block_entry = NULL;
   webm_ctx->block_frame_index = 0;
   webm_ctx->timestamp_ns = 0;
+  webm_ctx->reached_eos = 0;
 
   return 0;
 }