Dart2js Avoid file-names of deferred .part-files from getting too long.

Dart2js Avoid file-names of deferred .part-files from getting too long.

R=johnniwinther@google.com

Committed: https://code.google.com/p/dart/source/detail?r=38000

[Johnni Winther, 2014-07-03 11:08:14]

lgtm

[sigurdm, 2014-07-04 07:51:54]

Committed patchset #1 manually as r38000 (presubmit successful).

[Alan Knight, 2014-07-07 20:08:07]

https://codereview.chromium.org/368193004/diff/1/sdk/lib/_internal/compiler/i...
File sdk/lib/_internal/compiler/implementation/deferred_load.dart (right):

https://codereview.chromium.org/368193004/diff/1/sdk/lib/_internal/compiler/i...
sdk/lib/_internal/compiler/implementation/deferred_load.dart:572: String
suggestedName = importNames.join('_');
Is this going to run into potential problems with non-uniqueness. e.g. suppose I
have 100 deferred libraries all named
    deferred_locale_datetime_data_<locale>.dart
and another 100 named
    deferred_locale_number_data_<locale>.dart
and there is shared code between these two groups. 

Or is there only ever one file with the shared code? It seems like it might be
desirable to have multiples, but that's more of a nice-to-have.

[sigurdm, 2014-07-08 07:19:58]

https://codereview.chromium.org/368193004/diff/1/sdk/lib/_internal/compiler/i...
File sdk/lib/_internal/compiler/implementation/deferred_load.dart (right):

https://codereview.chromium.org/368193004/diff/1/sdk/lib/_internal/compiler/i...
sdk/lib/_internal/compiler/implementation/deferred_load.dart:572: String
suggestedName = importNames.join('_');
We take care of the uniqueness a few lines further down.

outputUnit.name = makeUnique(suggestedName, usedOutputUnitNames);