Add config flag to only enable normal tile mode

BUG=aomedia:2032

Change-Id: I1c5f58ece31fa25718bc7d99c7be8947560f55dd

av1/decoder/obu.c

diff --git a/av1/decoder/obu.c b/av1/decoder/obu.c
index f52035b..1ad70b5 100644
--- a/av1/decoder/obu.c
+++ b/av1/decoder/obu.c
@@ -938,6 +938,11 @@
         decoded_payload_size = read_metadata(data, payload_size);
         break;
       case OBU_TILE_LIST:
+        if (CONFIG_NORMAL_TILE_MODE) {
+          cm->error.error_code = AOM_CODEC_UNSUP_BITSTREAM;
+          return -1;
+        }
+
         // This OBU type is purely for the large scale tile coding mode.
         // The common camera frame header has to be already decoded.
         if (!pbi->camera_frame_header_ready) {

build/cmake/aom_config_defaults.cmake

diff --git a/build/cmake/aom_config_defaults.cmake b/build/cmake/aom_config_defaults.cmake
index 2561b98..6191947 100644
--- a/build/cmake/aom_config_defaults.cmake
+++ b/build/cmake/aom_config_defaults.cmake
@@ -82,6 +82,7 @@
 set(CONFIG_INTERNAL_STATS 0 CACHE NUMBER "Enables internal encoder stats.")
 set(CONFIG_LOWBITDEPTH 0 CACHE NUMBER "Enables 8-bit optimized pipeline.")
 set(CONFIG_MAX_DECODE_PROFILE 2 CACHE NUMBER "Max profile to support decoding.")
+set(CONFIG_NORMAL_TILE_MODE 0 CACHE NUMBER "Only enables normal tile mode.")
 set(CONFIG_SIZE_LIMIT 0 CACHE NUMBER "Limit max decode width/height.")
 set(CONFIG_SPATIAL_RESAMPLING 1 CACHE NUMBER "Spatial resampling.")
 set(DECODE_HEIGHT_LIMIT 0 CACHE NUMBER "Set limit for decode height.")