Merge "Prevent decoder from using uninitialized entropy context."

diff --cc vp9/decoder/vp9_decodeframe.c
index 58df87d,470b2ba..5bf44d7
--- 1/vp9/decoder/vp9_decodeframe.c
--- 2/vp9/decoder/vp9_decodeframe.c
+++ b/vp9/decoder/vp9_decodeframe.c
@@@ -1556,7 -1558,12 +1556,11 @@@ void vp9_decode_frame(VP9Decoder *pbi
    vp9_setup_block_planes(xd, cm->subsampling_x, cm->subsampling_y);
  
    *cm->fc = cm->frame_contexts[cm->frame_context_idx];
+   if (!cm->fc->initialized)
+     vpx_internal_error(&cm->error, VPX_CODEC_CORRUPT_FRAME,
+                        "Uninitialized entropy context.");
+ 
    vp9_zero(cm->counts);
 -  vp9_zero(xd->dqcoeff);
  
    xd->corrupted = 0;
    new_fb->corrupted = read_compressed_header(pbi, data, first_partition_size);