Define MAX_TRANSFORM_BITS according to the specification.

Change-Id: I0d575aa84e143bea56b55deb8f42b44e13dd5f1e

diff --git a/src/enc/vp8l_enc.c b/src/enc/vp8l_enc.c
index 44cb0b6..1cac0ab 100644
--- a/src/enc/vp8l_enc.c
+++ b/src/enc/vp8l_enc.c

@@ -1084,7 +1084,7 @@
   }
   VP8LPutBits(bw, TRANSFORM_PRESENT, 1);
   VP8LPutBits(bw, PREDICTOR_TRANSFORM, 2);
-  assert(pred_bits >= MIN_TRANSFORM_BITS);
+  assert(pred_bits >= MIN_TRANSFORM_BITS && pred_bits <= MAX_TRANSFORM_BITS);
   VP8LPutBits(bw, pred_bits - MIN_TRANSFORM_BITS, NUM_TRANSFORM_BITS);
   return EncodeImageNoHuffman(
       bw, enc->transform_data_, (VP8LHashChain*)&enc->hash_chain_,
@@ -1108,7 +1108,8 @@
   }
   VP8LPutBits(bw, TRANSFORM_PRESENT, 1);
   VP8LPutBits(bw, CROSS_COLOR_TRANSFORM, 2);
-  assert(ccolor_transform_bits >= MIN_TRANSFORM_BITS);
+  assert(ccolor_transform_bits >= MIN_TRANSFORM_BITS &&
+         ccolor_transform_bits <= MAX_TRANSFORM_BITS);
   VP8LPutBits(bw, ccolor_transform_bits - MIN_TRANSFORM_BITS,
               NUM_TRANSFORM_BITS);
   return EncodeImageNoHuffman(

diff --git a/src/enc/vp8li_enc.h b/src/enc/vp8li_enc.h
index 2f04b6d..59006cf 100644
--- a/src/enc/vp8li_enc.h
+++ b/src/enc/vp8li_enc.h

@@ -34,7 +34,7 @@
 #endif
 
 // maximum value of transform_bits_ in VP8LEncoder.
-#define MAX_TRANSFORM_BITS 6
+#define MAX_TRANSFORM_BITS (MIN_TRANSFORM_BITS + (1 << NUM_TRANSFORM_BITS) - 1)
 
 typedef enum {
   kEncoderNone = 0,