[fuchsia] Update to zx_cprng_draw_new

This version doesn't have short reads. We'll eventually rename the
syscall back to zx_cprng_draw once all the clients have migrated to the
new semantics.

Change-Id: I7a7f6751e4d85dcc9b0a03a533dd93f3cbee277f
Reviewed-on: https://boringssl-review.googlesource.com/29084
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>

crypto/rand_extra/fuchsia.c

diff --git a/crypto/rand_extra/fuchsia.c b/crypto/rand_extra/fuchsia.c
index ce8356c..0a0d7f0 100644
--- a/crypto/rand_extra/fuchsia.c
+++ b/crypto/rand_extra/fuchsia.c
@@ -29,14 +29,12 @@
     if (requested < output_bytes_this_pass) {
       output_bytes_this_pass = requested;
     }
-    size_t bytes_drawn;
-    zx_status_t status =
-        zx_cprng_draw(out, output_bytes_this_pass, &bytes_drawn);
+    zx_status_t status = zx_cprng_draw_new(out, output_bytes_this_pass);
     if (status != ZX_OK) {
       abort();
     }
-    requested -= bytes_drawn;
-    out += bytes_drawn;
+    requested -= output_bytes_this_pass;
+    out += output_bytes_this_pass;
   }
 }