Detect unsupported OBU type

BUG=aomedia:1456
BUG=aomedia:1457
BUG=aomedia:1458
BUG=aomedia:1460
BUG=aomedia:1462
BUG=aomedia:1463
BUG=aomedia:1464
BUG=aomedia:1465

Change-Id: I72f20425c3d90f4fb4af3955e27573e776fc4986

av1/decoder/obu.c

diff --git a/av1/decoder/obu.c b/av1/decoder/obu.c
index 264b95e..ba291e1 100644
--- a/av1/decoder/obu.c
+++ b/av1/decoder/obu.c
@@ -359,7 +359,11 @@
       case OBU_METADATA:
         obu_payload_size = read_metadata(data, obu_size);
         break;
-      default: break;
+      case OBU_PADDING:
+      default:
+        // Skip padding and unknown obus for now.
+        obu_payload_size = obu_size;
+        break;
     }
 
     data += obu_payload_size;