Remove unnecessary HandleScope

This is a clean-up for previous CL:
https://chromium-review.googlesource.com/c/chromium/src/+/1215512

Bug: 872138
Change-Id: I2be8ab98d9d42404936779bb55cba1a0c5f00742
Reviewed-on: https://chromium-review.googlesource.com/c/1275989
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Yuki Shiino <yukishiino@chromium.org>
Commit-Queue: Yuki Yamada <yukiy@google.com>
Cr-Commit-Position: refs/heads/master@{#598735}
1 file changed