Prepare to convert various types to size_t.

webrtc/modules/audio_coding/codecs/isac/fix/source/lattice_c.c

Index: webrtc/modules/audio_coding/codecs/isac/fix/source/lattice_c.c
diff --git a/webrtc/modules/audio_coding/codecs/isac/fix/source/lattice_c.c b/webrtc/modules/audio_coding/codecs/isac/fix/source/lattice_c.c
index 8c53b0bf3225f0b1f2310b0d228558ec3b90d6a4..43a15794321a8649c7ae67f3029f304cc5b51cf3 100644
--- a/webrtc/modules/audio_coding/codecs/isac/fix/source/lattice_c.c
+++ b/webrtc/modules/audio_coding/codecs/isac/fix/source/lattice_c.c
@@ -35,11 +35,13 @@ void WebRtcIsacfix_FilterArLoop(int16_t* ar_g_Q0,     // Input samples
     int32_t tmp32_2 = 0;
 
     tmpAR = ar_f_Q0[n + 1];
-    for (k = order_coef - 1; k >= 0; k--) {
-      tmp32 = (cth_Q15[k] * tmpAR - sth_Q15[k] * ar_g_Q0[k] + 16384) >> 15;
-      tmp32_2 = (sth_Q15[k] * tmpAR + cth_Q15[k] * ar_g_Q0[k] + 16384) >> 15;
+    for (k = order_coef; k > 0; k--) {
+      tmp32 = (cth_Q15[k - 1] * tmpAR - sth_Q15[k - 1] * ar_g_Q0[k - 1] +
+               16384) >> 15;
+      tmp32_2 = (sth_Q15[k - 1] * tmpAR + cth_Q15[k - 1] * ar_g_Q0[k - 1] +
+                 16384) >> 15;
       tmpAR   = (int16_t)WebRtcSpl_SatW32ToW16(tmp32);
-      ar_g_Q0[k + 1] = (int16_t)WebRtcSpl_SatW32ToW16(tmp32_2);
+      ar_g_Q0[k] = (int16_t)WebRtcSpl_SatW32ToW16(tmp32_2);
     }
     ar_f_Q0[n + 1] = tmpAR;
     ar_g_Q0[0] = tmpAR;