Document session cache functions.

Also switch to the new variable names (SSL_CTX *ctx, SSL *ssl,
SSL_SESSION *session) for all documented functions.

Change-Id: I15e15a703b96af1727601108223c7ce3b0691f1d
Reviewed-on: https://boringssl-review.googlesource.com/5882
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c
index a70d55a..a1f7243 100644
--- a/ssl/ssl_lib.c
+++ b/ssl/ssl_lib.c
@@ -918,8 +918,8 @@
 }
 
 int SSL_CTX_set_session_id_context(SSL_CTX *ctx, const uint8_t *sid_ctx,
-                                   unsigned int sid_ctx_len) {
-  if (sid_ctx_len > sizeof ctx->sid_ctx) {
+                                   unsigned sid_ctx_len) {
+  if (sid_ctx_len > sizeof(ctx->sid_ctx)) {
     OPENSSL_PUT_ERROR(SSL, SSL_R_SSL_SESSION_ID_CONTEXT_TOO_LONG);
     return 0;
   }
@@ -930,7 +930,7 @@
 }
 
 int SSL_set_session_id_context(SSL *ssl, const uint8_t *sid_ctx,
-                               unsigned int sid_ctx_len) {
+                               unsigned sid_ctx_len) {
   if (sid_ctx_len > SSL_MAX_SID_CTX_LENGTH) {
     OPENSSL_PUT_ERROR(SSL, SSL_R_SSL_SESSION_ID_CONTEXT_TOO_LONG);
     return 0;
@@ -952,7 +952,7 @@
 }
 
 int SSL_has_matching_session_id(const SSL *ssl, const uint8_t *id,
-                                unsigned int id_len) {
+                                unsigned id_len) {
   /* A quick examination of SSL_SESSION_hash and SSL_SESSION_cmp shows how we
    * can "construct" a session to give us the desired check - ie. to find if
    * there's a session in the hash table that would conflict with any new