Add noexcept to callback_internal.cc stuff to align its header

Move ctor and assign of CallbackBase get marked as noexcept recently,
but they are not match to correspondings in .cc. That causes a build
failure on some of bots.

Change-Id: I0af0a3224147e13b526678c791199a54f87b988d
Reviewed-on: https://chromium-review.googlesource.com/1067318
Reviewed-by: Shinya Kawanaka <shinyak@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Commit-Queue: Taiju Tsuiki <tzik@chromium.org>
Cr-Commit-Position: refs/heads/master@{#560246}
1 file changed