Convert more users of grpc_slice_unref --> grpc_slice_unref_internal
diff --git a/src/core/lib/security/credentials/composite/composite_credentials.c b/src/core/lib/security/credentials/composite/composite_credentials.c
index d55d00b..be1588d 100644
--- a/src/core/lib/security/credentials/composite/composite_credentials.c
+++ b/src/core/lib/security/credentials/composite/composite_credentials.c
@@ -54,18 +54,20 @@
   grpc_credentials_metadata_cb cb;
 } grpc_composite_call_credentials_metadata_context;
 
-static void composite_call_destruct(grpc_call_credentials *creds) {
+static void composite_call_destruct(grpc_exec_ctx *exec_ctx,
+                                    grpc_call_credentials *creds) {
   grpc_composite_call_credentials *c = (grpc_composite_call_credentials *)creds;
   size_t i;
   for (i = 0; i < c->inner.num_creds; i++) {
-    grpc_call_credentials_unref(c->inner.creds_array[i]);
+    grpc_call_credentials_unref(exec_ctx, c->inner.creds_array[i]);
   }
   gpr_free(c->inner.creds_array);
 }
 
 static void composite_call_md_context_destroy(
+    grpc_exec_ctx *exec_ctx,
     grpc_composite_call_credentials_metadata_context *ctx) {
-  grpc_credentials_md_store_unref(ctx->md_elems);
+  grpc_credentials_md_store_unref(exec_ctx, ctx->md_elems);
   gpr_free(ctx);
 }
 
@@ -103,7 +105,7 @@
   /* We're done!. */
   ctx->cb(exec_ctx, ctx->user_data, ctx->md_elems->entries,
           ctx->md_elems->num_entries, GRPC_CREDENTIALS_OK, NULL);
-  composite_call_md_context_destroy(ctx);
+  composite_call_md_context_destroy(exec_ctx, ctx);
 }
 
 static void composite_call_get_request_metadata(
@@ -209,17 +211,19 @@
 
 /* -- Composite channel credentials. -- */
 
-static void composite_channel_destruct(grpc_channel_credentials *creds) {
+static void composite_channel_destruct(grpc_exec_ctx *exec_ctx,
+                                       grpc_channel_credentials *creds) {
   grpc_composite_channel_credentials *c =
       (grpc_composite_channel_credentials *)creds;
-  grpc_channel_credentials_unref(c->inner_creds);
-  grpc_call_credentials_unref(c->call_creds);
+  grpc_channel_credentials_unref(exec_ctx, c->inner_creds);
+  grpc_call_credentials_unref(exec_ctx, c->call_creds);
 }
 
 static grpc_security_status composite_channel_create_security_connector(
-    grpc_channel_credentials *creds, grpc_call_credentials *call_creds,
-    const char *target, const grpc_channel_args *args,
-    grpc_channel_security_connector **sc, grpc_channel_args **new_args) {
+    grpc_exec_ctx *exec_ctx, grpc_channel_credentials *creds,
+    grpc_call_credentials *call_creds, const char *target,
+    const grpc_channel_args *args, grpc_channel_security_connector **sc,
+    grpc_channel_args **new_args) {
   grpc_composite_channel_credentials *c =
       (grpc_composite_channel_credentials *)creds;
   grpc_security_status status = GRPC_SECURITY_ERROR;
@@ -233,11 +237,12 @@
     grpc_call_credentials *composite_call_creds =
         grpc_composite_call_credentials_create(c->call_creds, call_creds, NULL);
     status = c->inner_creds->vtable->create_security_connector(
-        c->inner_creds, composite_call_creds, target, args, sc, new_args);
-    grpc_call_credentials_unref(composite_call_creds);
+        exec_ctx, c->inner_creds, composite_call_creds, target, args, sc,
+        new_args);
+    grpc_call_credentials_unref(exec_ctx, composite_call_creds);
   } else {
     status = c->inner_creds->vtable->create_security_connector(
-        c->inner_creds, c->call_creds, target, args, sc, new_args);
+        exec_ctx, c->inner_creds, c->call_creds, target, args, sc, new_args);
   }
   return status;
 }