Add rtc::Optional::emplace

Add rtc::Optional::emplace

BUG=None

Committed: https://crrev.com/9e83c97e9fedb633675b419221ba9a74f688ca58
Cr-Commit-Position: refs/heads/master@{#14659}

[danilchap, 2016-10-17 15:29:00]

danilchap@webrtc.org changed reviewers:
+ kwiberg@webrtc.org

[danilchap, 2016-10-17 15:29:00]

Simple implementation of the emplace:
I went for always destroy before reconstruct, instead of forcing move assignment
when applicable.
That kind of optimization would complicate code too much since we do not even
have std/rtc ::is_move_assignable

[kwiberg-webrtc, 2016-10-18 08:46:19]

lgtm, if you limit the scope of of clang-non-formatting.

https://codereview.webrtc.org/2424063002/diff/40001/webrtc/base/optional.h
File webrtc/base/optional.h (right):

https://codereview.webrtc.org/2424063002/diff/40001/webrtc/base/optional.h#ne...
webrtc/base/optional.h:204: }
Yes, it sounds right to destroy + create new rather than try to use move
assignment. From cppreference.com: "Constructs the contained value in-place. If
*this already contains a value before the call, the contained value is destroyed
by calling its destructor."

https://codereview.webrtc.org/2424063002/diff/40001/webrtc/base/optional_unit...
File webrtc/base/optional_unittest.cc (right):

https://codereview.webrtc.org/2424063002/diff/40001/webrtc/base/optional_unit...
webrtc/base/optional_unittest.cc:399: // clang-format off
Please don't switch off clang-format for such a large region. Do it just around
the EXPECT_EQ statements you want to protect.

[danilchap, 2016-10-18 10:37:31]

https://codereview.webrtc.org/2424063002/diff/40001/webrtc/base/optional_unit...
File webrtc/base/optional_unittest.cc (right):

https://codereview.webrtc.org/2424063002/diff/40001/webrtc/base/optional_unit...
webrtc/base/optional_unittest.cc:399: // clang-format off
On 2016/10/18 08:46:19, kwiberg-webrtc wrote:
> Please don't switch off clang-format for such a large region. Do it just
around
> the EXPECT_EQ statements you want to protect.

Done.

[danilchap, 2016-10-18 10:53:25]

The CQ bit was checked by danilchap@webrtc.org

[danilchap, 2016-10-18 10:53:25]

The patchset sent to the CQ was uploaded after l-g-t-m from kwiberg@webrtc.org
Link to the patchset: https://codereview.webrtc.org/2424063002/#ps60001 (title:
"Feedback")

[commit-bot: I haz the power, 2016-10-18 10:53:27]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.webrtc.org/...

[commit-bot: I haz the power, 2016-10-18 11:07:21]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2016-10-18 11:07:27]

Description was changed from

==========
Add rtc::Optional::emplace

BUG=None
==========

to

==========
Add rtc::Optional::emplace

BUG=None

Committed: https://crrev.com/9e83c97e9fedb633675b419221ba9a74f688ca58
Cr-Commit-Position: refs/heads/master@{#14659}
==========

[commit-bot: I haz the power, 2016-10-18 11:07:28]

Patchset 4 (id:??) landed as
https://crrev.com/9e83c97e9fedb633675b419221ba9a74f688ca58
Cr-Commit-Position: refs/heads/master@{#14659}