dart2js: Make sure '_globalState' is set before calling `computeThisScript`.

Make sure '_globalState' is set before calling `computeThisScript`.

As first line of running `_globalState = new _Manager()` we invoked `_nativeDetectEnvironment()`. However, that one could ending up calling the getter `IsolateNatives.thisScript` which, in turn could need `_globalState`. Since the state wasn't set yet, this yielded a NPE.

R=sigmund@google.com

Committed: https://github.com/dart-lang/sdk/commit/ffb72ee8170eed364b3ec500ac0a0097d359a143

[floitsch, 2015-07-31 17:49:06]

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

[floitsch, 2015-07-31 17:49:06]

Several things:
- this can only be triggered in an environment where isWorker is false, and the
script is not available either. I think this can only happen in extensions.

- this only happens if the program needs isolates (which, unfortunately,
currently is also the case, when 'async' is used).

- another solution would be to call IsolateNatives.computeScript() directly, and
pass the `isWorker` flag as argument. I'm not sure if that's better...

[Siggi Cherem (dart-lang), 2015-07-31 18:04:05]

lgtm

I'm fine with either approach too.

[floitsch, 2015-08-03 08:37:36]

On 2015/07/31 18:04:05, Siggi Cherem (dart-lang) wrote:
> lgtm
> 
> I'm fine with either approach too.

Going with this one, then.
Eventually we should clean up the isolate code anyway...

[floitsch, 2015-08-03 08:37:46]

Committed patchset #2 (id:20001) manually as
ffb72ee8170eed364b3ec500ac0a0097d359a143 (presubmit successful).