Change AV1E_SET_MAX_CONSEC_FRAME_DROP_CBR to int

Change the parameter type of AV1E_SET_MAX_CONSEC_FRAME_DROP_CBR from
unsigned int to int because this value is stored in a struct member of
the int type. Change the codec control to return AOM_CODEC_INVALID_PARAM
if the value is negative.

Document the parameter type in the comment.

Note: A follow-up to
https: //aomedia-review.googlesource.com/c/aom/+/182921.
Change-Id: I99e6180358c1cdf72cf7a9ad32a138e784c8d461

aom/aomcx.h

diff --git a/aom/aomcx.h b/aom/aomcx.h
index 8abc786..f061be3 100644
--- a/aom/aomcx.h
+++ b/aom/aomcx.h
@@ -1527,9 +1527,9 @@
    */
   AV1E_SET_BITRATE_ONE_PASS_CBR = 163,
 
-  /*!\brief Codec control to set the maxium number of consecutive frame drops
-   * allowed for the frame_dropper in 1 pass CBR mode. Value of zero has no
-   * effect.
+  /*!\brief Codec control to set the maximum number of consecutive frame drops
+   * allowed for the frame dropper in 1 pass CBR mode, int parameter. Value of
+   * zero has no effect.
    */
   AV1E_SET_MAX_CONSEC_FRAME_DROP_CBR = 164,
 
@@ -2178,7 +2178,7 @@
 AOM_CTRL_USE_TYPE(AV1E_SET_BITRATE_ONE_PASS_CBR, unsigned int)
 #define AOM_CTRL_AV1E_SET_BITRATE_ONE_PASS_CBR
 
-AOM_CTRL_USE_TYPE(AV1E_SET_MAX_CONSEC_FRAME_DROP_CBR, unsigned int)
+AOM_CTRL_USE_TYPE(AV1E_SET_MAX_CONSEC_FRAME_DROP_CBR, int)
 #define AOM_CTRL_AV1E_SET_MAX_CONSEC_FRAME_DROP_CBR
 
 /*!\endcond */

av1/av1_cx_iface.c

diff --git a/av1/av1_cx_iface.c b/av1/av1_cx_iface.c
index 588b0a4..7256f48 100644
--- a/av1/av1_cx_iface.c
+++ b/av1/av1_cx_iface.c
@@ -2589,7 +2589,9 @@
     aom_codec_alg_priv_t *ctx, va_list args) {
   AV1_PRIMARY *const ppi = ctx->ppi;
   AV1_COMP *const cpi = ppi->cpi;
-  cpi->rc.max_consec_drop = CAST(AV1E_SET_MAX_CONSEC_FRAME_DROP_CBR, args);
+  const int max_consec_drop = CAST(AV1E_SET_MAX_CONSEC_FRAME_DROP_CBR, args);
+  if (max_consec_drop < 0) return AOM_CODEC_INVALID_PARAM;
+  cpi->rc.max_consec_drop = max_consec_drop;
   cpi->rc.drop_count_consec = 0;
   return AOM_CODEC_OK;
 }