Add Explicit Argument Guidance for time.h

Add Explicit Argument Guidance for time.h

This is similar to what is provided by StringPiece.

BUG=

Committed: https://crrev.com/b647179e487049dd2369ccdcea20bdc516e3fff5
Cr-Commit-Position: refs/heads/master@{#422241}

[robliao, 2016-09-30 19:50:01]

robliao@chromium.org changed reviewers:
+ danakj@chromium.org

[danakj, 2016-09-30 19:57:47]

https://codereview.chromium.org/2386723002/diff/1/base/time/time.h
File base/time/time.h (right):

https://codereview.chromium.org/2386723002/diff/1/base/time/time.h#newcode25
base/time/time.h:25: // instance. Thus, they can be efficiently passed by-value
(as opposed to
This is already said here though?

https://codereview.chromium.org/2386723002/diff/1/base/time/time.h#newcode31
base/time/time.h:31: //   void MyFunction(const TimeDelta& arg);  // not
preferred
nit:  // Not preferred.

[robliao, 2016-09-30 20:03:06]

https://codereview.chromium.org/2386723002/diff/1/base/time/time.h
File base/time/time.h (right):

https://codereview.chromium.org/2386723002/diff/1/base/time/time.h#newcode25
base/time/time.h:25: // instance. Thus, they can be efficiently passed by-value
(as opposed to
On 2016/09/30 19:57:47, danakj wrote:
> This is already said here though?

Agreed this discusses it, but in a non-opinionated way. This discussion below
makes an opinion on the best-practice. 

This came up in a code review earlier
(https://codereview.chromium.org/2383193002/). For StringPieces, we can simply
point to that comment. It's a little less clear with respect to time.h

https://codereview.chromium.org/2386723002/diff/1/base/time/time.h#newcode31
base/time/time.h:31: //   void MyFunction(const TimeDelta& arg);  // not
preferred
On 2016/09/30 19:57:47, danakj wrote:
> nit:  // Not preferred.

Done.

[danakj, 2016-09-30 20:18:56]

LGTM but lets make it less redundant?

https://codereview.chromium.org/2386723002/diff/20001/base/time/time.h
File base/time/time.h (right):

https://codereview.chromium.org/2386723002/diff/20001/base/time/time.h#newcode28
base/time/time.h:28: // Prefer passing these classes by value:
can you combine these two comments then cuz saying it twice is weird. like..

As time classes occupy 64-bits per instance, prefer passing these classes by
value:

or something?

[robliao, 2016-09-30 20:26:30]

https://codereview.chromium.org/2386723002/diff/20001/base/time/time.h
File base/time/time.h (right):

https://codereview.chromium.org/2386723002/diff/20001/base/time/time.h#newcode28
base/time/time.h:28: // Prefer passing these classes by value:
On 2016/09/30 20:18:56, danakj wrote:
> can you combine these two comments then cuz saying it twice is weird. like..
> 
> As time classes occupy 64-bits per instance, prefer passing these classes by
> value:
> 
> or something?

Done!

// All time classes are copyable, assignable, and occupy 64-bits per instance.
// As a result, prefer passing them by value:
//   void MyFunction(TimeDelta arg);
// If circumstances require, you may also pass by const reference:
//   void MyFunction(const TimeDelta& arg);  // Not preferred.

[robliao, 2016-09-30 20:27:04]

The CQ bit was checked by robliao@chromium.org

[robliao, 2016-09-30 20:27:04]

The patchset sent to the CQ was uploaded after l-g-t-m from danakj@chromium.org
Link to the patchset: https://codereview.chromium.org/2386723002/#ps40001
(title: "Update Wording")

[commit-bot: I haz the power, 2016-09-30 20:27:31]

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

[commit-bot: I haz the power, 2016-09-30 22:25:55]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-09-30 22:28:25]

Description was changed from

==========
Add Explicit Argument Guidance for time.h

This is similar to what is provided by StringPiece.

BUG=
==========

to

==========
Add Explicit Argument Guidance for time.h

This is similar to what is provided by StringPiece.

BUG=

Committed: https://crrev.com/b647179e487049dd2369ccdcea20bdc516e3fff5
Cr-Commit-Position: refs/heads/master@{#422241}
==========

[commit-bot: I haz the power, 2016-09-30 22:28:26]

Patchset 3 (id:??) landed as
https://crrev.com/b647179e487049dd2369ccdcea20bdc516e3fff5
Cr-Commit-Position: refs/heads/master@{#422241}