Minor refactor to match the 4x4 forward transform.

Change-Id: Ib5337dfa78b73059ad169ca98a07119aa991864b
diff --git a/av1/common/idct.c b/av1/common/idct.c
index 8f4e58a..49a91fb 100644
--- a/av1/common/idct.c
+++ b/av1/common/idct.c
@@ -249,6 +249,10 @@
 void av1_iht4x4_16_add_c(const tran_low_t *input, uint8_t *dest, int stride,
                          const INV_TXFM_PARAM *param) {
   int tx_type = param->tx_type;
+  if (tx_type == DCT_DCT) {
+    aom_idct4x4_16_add(input, dest, stride);
+    return;
+  }
   static const transform_2d IHT_4[] = {
     { aom_idct4_c, aom_idct4_c },    // DCT_DCT  = 0
     { aom_iadst4_c, aom_idct4_c },   // ADST_DCT = 1
@@ -1303,15 +1307,17 @@
 
 // idct
 void av1_idct4x4_add(const tran_low_t *input, uint8_t *dest, int stride,
-                     int eob) {
+                     const INV_TXFM_PARAM *param) {
+  const int eob = param->eob;
   if (eob > 1)
-    aom_idct4x4_16_add(input, dest, stride);
+    av1_iht4x4_16_add(input, dest, stride, param);
   else
     aom_idct4x4_1_add(input, dest, stride);
 }
 
 void av1_iwht4x4_add(const tran_low_t *input, uint8_t *dest, int stride,
-                     int eob) {
+                     const INV_TXFM_PARAM *param) {
+  const int eob = param->eob;
   if (eob > 1)
     aom_iwht4x4_16_add(input, dest, stride);
   else
@@ -1427,15 +1433,14 @@
 static void inv_txfm_add_4x4(const tran_low_t *input, uint8_t *dest, int stride,
                              const INV_TXFM_PARAM *param) {
   const TX_TYPE tx_type = param->tx_type;
-  const int eob = param->eob;
   if (param->lossless) {
     assert(tx_type == DCT_DCT);
-    av1_iwht4x4_add(input, dest, stride, eob);
+    av1_iwht4x4_add(input, dest, stride, param);
     return;
   }
 
   switch (tx_type) {
-    case DCT_DCT: av1_idct4x4_add(input, dest, stride, eob); break;
+    case DCT_DCT: av1_idct4x4_add(input, dest, stride, param); break;
     case ADST_DCT:
     case DCT_ADST:
     case ADST_ADST:
diff --git a/av1/common/idct.h b/av1/common/idct.h
index 3c2fa6a..0591d4a 100644
--- a/av1/common/idct.h
+++ b/av1/common/idct.h
@@ -76,9 +76,9 @@
 int av1_get_tx_scale(const TX_SIZE tx_size);
 
 void av1_iwht4x4_add(const tran_low_t *input, uint8_t *dest, int stride,
-                     int eob);
+                     const INV_TXFM_PARAM *inv_txfm_param);
 void av1_idct4x4_add(const tran_low_t *input, uint8_t *dest, int stride,
-                     int eob);
+                     const INV_TXFM_PARAM *inv_txfm_param);
 
 void av1_inv_txfm_add(const tran_low_t *input, uint8_t *dest, int stride,
                       INV_TXFM_PARAM *inv_txfm_param);
diff --git a/av1/encoder/encodemb.c b/av1/encoder/encodemb.c
index a9e2f2a..b6301aa 100644
--- a/av1/encoder/encodemb.c
+++ b/av1/encoder/encodemb.c
@@ -822,6 +822,7 @@
   struct macroblock_plane *const p = &x->plane[plane];
   struct macroblockd_plane *const pd = &xd->plane[plane];
   tran_low_t *const dqcoeff = BLOCK_OFFSET(pd->dqcoeff, block);
+  INV_TXFM_PARAM inv_txfm_param;
   uint8_t *dst;
   int ctx = 0;
   dst = &pd->dst
@@ -857,12 +858,11 @@
 #endif  // CONFIG_HIGHBITDEPTH
     }
 #endif  // !CONFIG_PVQ
-#if CONFIG_HIGHBITDEPTH
-    INV_TXFM_PARAM inv_txfm_param;
     inv_txfm_param.bd = xd->bd;
     inv_txfm_param.tx_type = DCT_DCT;
     inv_txfm_param.eob = p->eobs[block];
     inv_txfm_param.lossless = xd->lossless[xd->mi[0]->mbmi.segment_id];
+#if CONFIG_HIGHBITDEPTH
     if (xd->cur_buf->flags & YV12_FLAG_HIGHBITDEPTH) {
       av1_highbd_inv_txfm_add_4x4(dqcoeff, dst, pd->dst.stride,
                                   &inv_txfm_param);
@@ -870,9 +870,9 @@
     }
 #endif  //  CONFIG_HIGHBITDEPTH
     if (xd->lossless[xd->mi[0]->mbmi.segment_id]) {
-      av1_iwht4x4_add(dqcoeff, dst, pd->dst.stride, p->eobs[block]);
+      av1_iwht4x4_add(dqcoeff, dst, pd->dst.stride, &inv_txfm_param);
     } else {
-      av1_idct4x4_add(dqcoeff, dst, pd->dst.stride, p->eobs[block]);
+      av1_idct4x4_add(dqcoeff, dst, pd->dst.stride, &inv_txfm_param);
     }
   }
 }