Only parse the directives when rewriting imports.

Only parse the directives when rewriting imports.

This shaves about 13% (a little under a second) off the time it
takes to load the asset environment for TodoMVC in my tests.

R=brianwilkerson@google.com, nweiz@google.com

Committed: https://code.google.com/p/dart/source/detail?r=36960

[Bob Nystrom, 2014-06-03 20:55:18]

Anders, I tried your solution. It's a good bit faster, but it also has a bug: it
doesn't return the future from apply(). If you fix that, it slows down
noticeably. It's still a tiny bit faster than what I'm doing here, but this is a
lot simpler and more reliable since the analyzer's parser has very solid
coverage.

[nweiz, 2014-06-03 21:23:08]

lgtm

https://codereview.chromium.org/314583007/diff/1/pkg/analyzer/lib/analyzer.dart
File pkg/analyzer/lib/analyzer.dart (right):

https://codereview.chromium.org/314583007/diff/1/pkg/analyzer/lib/analyzer.da...
pkg/analyzer/lib/analyzer.dart:78: /// being parsed.
Document [suppressErrors] as well.

https://codereview.chromium.org/314583007/diff/1/pkg/analyzer/lib/analyzer.da...
pkg/analyzer/lib/analyzer.dart:79: CompilationUnit parseDirectives(String
contents,
Probably a good idea to add a CHANGELOG entry about this.

[jwren, 2014-06-03 21:37:01]

LGTM, adding Konstantin too.

[scheglov, 2014-06-03 21:39:57]

LGTM

[Bob Nystrom, 2014-06-03 21:46:59]

https://codereview.chromium.org/314583007/diff/1/pkg/analyzer/lib/analyzer.dart
File pkg/analyzer/lib/analyzer.dart (right):

https://codereview.chromium.org/314583007/diff/1/pkg/analyzer/lib/analyzer.da...
pkg/analyzer/lib/analyzer.dart:78: /// being parsed.
On 2014/06/03 21:23:09, nweiz wrote:
> Document [suppressErrors] as well.

Done.

https://codereview.chromium.org/314583007/diff/1/pkg/analyzer/lib/analyzer.da...
pkg/analyzer/lib/analyzer.dart:79: CompilationUnit parseDirectives(String
contents,
On 2014/06/03 21:23:09, nweiz wrote:
> Probably a good idea to add a CHANGELOG entry about this.

The analyzer package doesn't have a changelog.

[nweiz, 2014-06-03 23:06:57]

https://codereview.chromium.org/314583007/diff/1/pkg/analyzer/lib/analyzer.dart
File pkg/analyzer/lib/analyzer.dart (right):

https://codereview.chromium.org/314583007/diff/1/pkg/analyzer/lib/analyzer.da...
pkg/analyzer/lib/analyzer.dart:79: CompilationUnit parseDirectives(String
contents,
On 2014/06/03 21:46:59, Bob Nystrom wrote:
> On 2014/06/03 21:23:09, nweiz wrote:
> > Probably a good idea to add a CHANGELOG entry about this.
> 
> The analyzer package doesn't have a changelog.

Great opportunity to add one :).

[Brian Wilkerson, 2014-06-03 23:09:55]

LGTM

[Bob Nystrom, 2014-06-03 23:27:42]

Committed patchset #2 manually as r36960 (presubmit successful).