[NTP] Defer the voice JS file

It will be executed "when the page has finished parsing" which seems right
for this script.

Bug: 868432
Change-Id: Icb0fb03518aca785c7a3d8583bcbfaecd4cb1487
Reviewed-on: https://chromium-review.googlesource.com/1154365
Reviewed-by: Kristi Park <kristipark@chromium.org>
Commit-Queue: Mathieu Perreault <mathp@chromium.org>
Cr-Commit-Position: refs/heads/master@{#579295}
1 file changed