Fix shutdown crash in Sky

Fix shutdown crash in Sky

Previously, we would try to close some Dart persistent handles after destroying
the isolate. Now we revoke the weak pointers these handles are using to refer
to the isolate before trying to tear them down.

Fixes https://github.com/domokit/mojo/issues/233

R=chinmaygarde@google.com, eseidel@chromium.org

Committed: https://chromium.googlesource.com/external/mojo/+/3711d3565f7232d145909037bdbdf2e7dbbcbfa0

[Chinmay, 2015-06-10 19:48:50]

chinmaygarde@google.com changed reviewers:
+ chinmaygarde@google.com

[Chinmay, 2015-06-10 19:48:50]

lgtm

[eseidel, 2015-06-10 19:50:29]

eseidel@chromium.org changed reviewers:
+ eseidel@chromium.org
- chinmaygarde@google.com

[eseidel, 2015-06-10 19:50:30]

Can you make thsi more idiot proof?

[abarth-chromium, 2015-06-10 19:53:14]

On 2015/06/10 at 19:50:30, eseidel wrote:
> Can you make thsi more idiot proof?

Done.

[eseidel, 2015-06-10 19:56:40]

eseidel@chromium.org changed reviewers:
+ chinmaygarde@google.com

[eseidel, 2015-06-10 19:56:41]

lgtm

https://codereview.chromium.org/1175053002/diff/20001/sky/engine/tonic/dart_s...
File sky/engine/tonic/dart_state.cc (right):

https://codereview.chromium.org/1175053002/diff/20001/sky/engine/tonic/dart_s...
sky/engine/tonic/dart_state.cc:38: if (isolate_) {
I might have early returned instead.  but ok.

[eseidel, 2015-06-10 19:57:42]

Edit your CL to say "closes https://github.com/domokit/mojo/issues/233" for
magic to happen.

[eseidel, 2015-06-10 19:57:59]

https://help.github.com/articles/closing-issues-via-commit-messages/

[abarth-chromium, 2015-06-10 19:59:11]

Committed patchset #2 (id:20001) manually as
3711d3565f7232d145909037bdbdf2e7dbbcbfa0 (presubmit successful).