Implement conditional copy/move ctors/assign-operators.

BUG=784732
TEST=Ran trybot.

Change-Id: Iec5f9eaa7482d4e23f5bf2eea4b34c9cd867f89d
Reviewed-on: https://chromium-review.googlesource.com/856021
Commit-Queue: Hidehiko Abe <[email protected]>
Reviewed-by: danakj <[email protected]>
Cr-Commit-Position: refs/heads/master@{#532004}
2 files changed