Isolate library changes for leg support.

Isolate library changes for leg support.
Committed: https://code.google.com/p/dart/source/detail?r=5352

[ngeoffray, 2012-03-11 15:43:54]

Hi Siggi and Eli! I am currently trying to plug Frog's isolate library into the
leg compiler. Almost all can be shared, and we temporarily support the native
keyword on selected libraries (because of dom/html).

This change is very minimal, but it enables running isolate API with leg
already. I will follow-up with a CL that enables isolate support in leg.

https://chromiumcodereview.appspot.com/9662046/diff/1/lib/isolate/frog/isolat...
File lib/isolate/frog/isolateimpl.dart (right):

https://chromiumcodereview.appspot.com/9662046/diff/1/lib/isolate/frog/isolat...
lib/isolate/frog/isolateimpl.dart:22: ReceivePort _port;
I moved this code here because it can be shared between leg/frog. Let me know if
you prefer another place.

https://chromiumcodereview.appspot.com/9662046/diff/1/lib/isolate/frog/isolat...
lib/isolate/frog/isolateimpl.dart:157: void initGlobals() native
@'$initGlobals(this);';
Leg and Frog currently differ in where they put global state. This function will
be specialized for each compiler.

https://chromiumcodereview.appspot.com/9662046/diff/1/lib/isolate/frog/isolat...
lib/isolate/frog/isolateimpl.dart:177: void _setGlobals() native
@'$setGlobals(this);';
Ditto.

https://chromiumcodereview.appspot.com/9662046/diff/1/lib/isolate/frog/isolat...
lib/isolate/frog/isolateimpl.dart:356: if (!$globalState.supportsWorkers ||
$globalState.isWorker) return (void 0);
Currently leg recognizes JS undefined as Dart null. Frog can support both JS
null and undefined. So this change works for both compilers.

https://chromiumcodereview.appspot.com/9662046/diff/1/lib/isolate/frog/native...
File lib/isolate/frog/natives.js (right):

https://chromiumcodereview.appspot.com/9662046/diff/1/lib/isolate/frog/native...
lib/isolate/frog/natives.js:11: function $setGlobals(context) { $globals =
context.isolateStatics; }
That's the Frog specific implementation.

https://chromiumcodereview.appspot.com/9662046/diff/1/lib/isolate/isolate_leg...
File lib/isolate/isolate_leg.dart (left):

https://chromiumcodereview.appspot.com/9662046/diff/1/lib/isolate/isolate_leg...
lib/isolate/isolate_leg.dart:48: #native("frog/natives.js");
I had to create another file because leg does not understand the #native tag. We
don't have any plans on supporting it, but we can workaround it.

[Siggi Cherem (dart-lang), 2012-03-12 16:20:40]

lgtm

Hi Nicolas, thanks for the detail explanations in the code review! They
definitively made it easier to understand :)

[ngeoffray, 2012-03-12 20:03:21]

Thanks Siggi!