Move CrossThreadCopier from platform/ to wtf/

Move CrossThreadCopier from platform/ to wtf/

This CL
- Moves CrossThreadCopier to wtf/,
- Moves each specialization of CrossThreadCopier<T> to the T's header, and make
  T's header to include wtf/CrossThreadCopier.h.

BUG=624419

[hiroshige, 2016-07-06 10:21:30]

The CQ bit was checked by hiroshige@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-07-06 10:21:39]

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

[hiroshige, 2016-07-06 10:42:42]

Description was changed from

==========
Move CrossThreadCopier from platform to WTF

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

to

==========
Move CrossThreadCopier from platform/ to wtf/

BUG=624419
==========

[hiroshige, 2016-07-06 11:35:43]

The CQ bit was checked by hiroshige@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-07-06 11:35:58]

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

[hiroshige, 2016-07-06 11:42:33]

Description was changed from

==========
Move CrossThreadCopier from platform/ to wtf/

BUG=624419
==========

to

==========
Move CrossThreadCopier from platform/ to wtf/

This CL
- Moves CrossThreadCopier to wtf/,
- Moves each specialization of CrossThreadCopier<T> to the T's header, and make
  T's header to include wtf/CrossThreadCopier.h.

BUG=624419
==========

[hiroshige, 2016-07-06 11:44:40]

hiroshige@chromium.org changed reviewers:
+ tzik@chromium.org

[hiroshige, 2016-07-06 11:44:41]

PTAL.

[haraken, 2016-07-06 12:38:29]

This looks good, but I'd like to have an md file that explains how to write
CrossThreadCopier (in a follow-up CL). At a first glance, it's just mysterious
(e.g., CrossThreadCopierPassThrough) :)

[commit-bot: I haz the power, 2016-07-06 13:41:30]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-07-06 13:41:31]

Dry run: This issue passed the CQ dry run.

[sof, 2016-07-06 14:13:34]

sigbjornf@opera.com changed reviewers:
+ sigbjornf@opera.com

[sof, 2016-07-06 14:13:34]

https://codereview.chromium.org/2125003002/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/platform/CrossThreadFunctional.h (right):

https://codereview.chromium.org/2125003002/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/platform/CrossThreadFunctional.h:9: #include
"wtf/CrossThreadCopier.h"
Do you plan to move CrossThreadFunctional.h in a followup/later?

[tzik, 2016-07-06 15:00:59]

Looks good. Just as an idea: Is it possible / does it look cleaner if we make
CrossThreadCopier::copy an non-member function and remove CrossThreadCopier?

[Yuta Kitamura, 2016-07-07 07:45:57]

yutak@chromium.org changed reviewers:
+ yutak@chromium.org

[Yuta Kitamura, 2016-07-07 07:45:59]

LGTM.

Moving the concept of "cross-thread copiable" to wtf/ makes
sense, since the contents of CrossThreadCopier.h and
CrossThreadFunctional.h are self-contained and do not rely
on other stuff in platform/.

[I assume the answer to sof's question is "yes".]

https://codereview.chromium.org/2125003002/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/bindings/core/v8/SourceLocation.h (right):

https://codereview.chromium.org/2125003002/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/bindings/core/v8/SourceLocation.h:84: } // namespace
blink
nit: This comment is false now

https://codereview.chromium.org/2125003002/diff/20001/third_party/WebKit/Sour...
File third_party/WebKit/Source/wtf/CrossThreadCopierTest.cpp (right):

https://codereview.chromium.org/2125003002/diff/20001/third_party/WebKit/Sour...
third_party/WebKit/Source/wtf/CrossThreadCopierTest.cpp:86: } // namespace blink
Ditto