Re-introduce frame size check inadvertantly deleted

This patch adds back in code that checks that the frame
size lies within defined bounds was inadvertantly removed
by a previous patch:
https://gerrit.chromium.org/gerrit/#/c/70814/

Change-Id: If526570ba559260c4b7e98098bc75f7700ae7f97

vp9/decoder/vp9_decodeframe.c

diff --git a/vp9/decoder/vp9_decodeframe.c b/vp9/decoder/vp9_decodeframe.c
index 03b4df5..614bf4b 100644
--- a/vp9/decoder/vp9_decodeframe.c
+++ b/vp9/decoder/vp9_decodeframe.c
@@ -621,6 +621,11 @@
 }
 
 static void resize_context_buffers(VP9_COMMON *cm, int width, int height) {
+#if CONFIG_SIZE_LIMIT
+  if (width > DECODE_WIDTH_LIMIT || height > DECODE_HEIGHT_LIMIT)
+    vpx_internal_error(&cm->error, VPX_CODEC_CORRUPT_FRAME,
+                       "Width and height beyond allowed size.");
+#endif
   if (cm->width != width || cm->height != height) {
     // Change in frame size (assumption: color format does not change).
     if (cm->width == 0 || cm->height == 0 ||