Cleanup 1: split parts into their own libraries, remove unused imports

Cleanup 1: split parts into their own libraries for: tree, helpers, ssa, native.

In the case of ssa, I also removed references to AST nodes in ssa nodes that were unused, so now only the builder imports the AST.

I also got rid of unused imports from everywhere else in the code.

R=sra@google.com

Committed: https://github.com/dart-lang/sdk/commit/0f979d529d31f452301f54c24c58f5a85d6f97d5

[Siggi Cherem (dart-lang), 2016-03-03 18:14:48]

Description was changed from

==========
Cleanup 1: split parts into their own libraries for: tree, helpers, ssa, native.
In the case of ssa, I also removed references to AST nodes in ssa nodes that
were unused, so now only the builder imports the AST.
==========

to

==========
Cleanup 1: split parts into their own libraries for: tree, helpers, ssa, native.

In the case of ssa, I also removed references to AST nodes in ssa nodes that
were unused, so now only the builder imports the AST.

I also got rid of unused imports from everywhere else in the code.
==========

[Siggi Cherem (dart-lang), 2016-03-03 18:18:06]

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

[sra1, 2016-03-04 01:21:10]

lgtm

https://codereview.chromium.org/1762723002/diff/1/pkg/compiler/lib/src/ssa/va...
File pkg/compiler/lib/src/ssa/validate.dart (right):

https://codereview.chromium.org/1762723002/diff/1/pkg/compiler/lib/src/ssa/va...
pkg/compiler/lib/src/ssa/validate.dart:5: 
extra line

[Siggi Cherem (dart-lang), 2016-03-14 21:03:39]

Description was changed from

==========
Cleanup 1: split parts into their own libraries for: tree, helpers, ssa, native.

In the case of ssa, I also removed references to AST nodes in ssa nodes that
were unused, so now only the builder imports the AST.

I also got rid of unused imports from everywhere else in the code.
==========

to

==========
Cleanup 1: split parts into their own libraries for: tree, helpers, ssa, native.

In the case of ssa, I also removed references to AST nodes in ssa nodes that
were unused, so now only the builder imports the AST.

I also got rid of unused imports from everywhere else in the code.

R=sra@google.com

Committed:
https://github.com/dart-lang/sdk/commit/0f979d529d31f452301f54c24c58f5a85d6f97d5
==========

[Siggi Cherem (dart-lang), 2016-03-14 21:03:41]

Committed patchset #1 (id:1) manually as
0f979d529d31f452301f54c24c58f5a85d6f97d5 (presubmit successful).

[Siggi Cherem (dart-lang), 2016-03-14 21:05:30]

thanks

https://codereview.chromium.org/1762723002/diff/1/pkg/compiler/lib/src/ssa/va...
File pkg/compiler/lib/src/ssa/validate.dart (right):

https://codereview.chromium.org/1762723002/diff/1/pkg/compiler/lib/src/ssa/va...
pkg/compiler/lib/src/ssa/validate.dart:5: 
On 2016/03/04 01:21:10, sra1 wrote:
> extra line

Done.