Do not use the namer for naming closure elements.

Do not use the namer for naming closure elements.

BUG=
R=floitsch@google.com

Committed: https://code.google.com/p/dart/source/detail?r=44594

Revetered: https://code.google.com/p/dart/source/detail?r=44596

Committed: https://code.google.com/p/dart/source/detail?r=44656

[herhut, 2015-03-19 16:44:19]

herhut@google.com changed reviewers:
+ floitsch@google.com

[floitsch, 2015-03-19 16:49:41]

LGTM.

[herhut, 2015-03-20 08:41:50]

Committed patchset #1 (id:1) manually as 44594 (presubmit successful).

[herhut, 2015-03-20 10:01:04]

Patchset #2 (id:20001) has been deleted

[herhut, 2015-03-23 10:14:17]

PTAL

I had to change the naming scheme for boxfields as we generated illegal names
otherwise. Instead of making them fixed backend names, I now let the namer
decide. The normal namer will just stick to the proposed names but the minifying
namer has special support for boxfields (already had it).

[floitsch, 2015-03-23 16:07:43]

Still LGTM.

[herhut, 2015-03-24 09:40:10]

Committed patchset #2 (id:40001) manually as 44656 (presubmit successful).

[sra1, 2015-03-24 17:16:37]

sra@google.com changed reviewers:
+ sra@google.com

[sra1, 2015-03-24 17:16:37]

I'd like to understand the problem being solved here.
The unminified code is less readable and larger than before, which is a step in
the wrong direction.

We used to have:

  box_0.x_0 = 122;

now we have:

  _box_0._captured_x_0 = 122;

we should seek to generate something that looks a lot simpler, e.g.

  box.x = 122;

If the issue is interference with other selectors for .x, then we can have
private selectors that map to simply named fields.

Does the change rely on the program not already containing a field called
'_captured_x_0' somewhere else?