Merge "Improve 32x32 forward dct" into experimental

vp9/common/vp9_idct.h

@@ -61,4 +61,11 @@ static INLINE int dct_const_round_shift(int input) {
   assert(INT16_MIN <= rv && rv <= INT16_MAX);
   return rv;
 }
+
+static INLINE int dct_32_round(int input) {
+  int rv = (input + DCT_CONST_ROUNDING) >> DCT_CONST_BITS;
+  assert(-131072 <= rv && rv <= 131071);
+  return rv;
+}
+
 #endif