Avoid throwing exceptions on inter-frame communication

Avoid throwing exceptions on inter-frame communication.

R=vsm@google.com

Committed: https://code.google.com/p/dart/source/detail?r=41116

[ahe, 2014-10-13 11:11:30]

Patchset #1 (id:1) has been deleted

[ahe, 2014-10-13 11:36:22]

ahe@google.com changed reviewers:
+ justinfagnani@google.com

[ahe, 2014-10-13 11:36:23]

https://codereview.chromium.org/650093002/diff/30001/dart/sdk/lib/js/dart2js/...
File dart/sdk/lib/js/dart2js/js_dart2js.dart (right):

https://codereview.chromium.org/650093002/diff/30001/dart/sdk/lib/js/dart2js/...
dart/sdk/lib/js/dart2js/js_dart2js.dart:587: _defineProperty(o, propertyName,
dartProxy);
Perhaps the problem is here.

I'm using dart:js to work around a bug in dart:html which prevents me from
installing onerror handler on iframe.contentWindow. Both the main page, and the
iframe run dart2js output, and they both use
"___dart__$dart_dartObject_ZxYxX_0_" as the dispatch property.

Also, it appears that we always try to define the property on non-local objects.
This will throw on the second attempt (but since we swallow exceptions in
defineProperty this goes unnoticed.

I'm not attempting to fix this, someone more familiar with the code should look
at this. I'm simply trying to avoid throwing so many exceptions as it is making
debugging incremental compilation hard.

[vsm, 2014-10-13 15:38:44]

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

[vsm, 2014-10-13 15:38:44]

lgtm

is there a corresponding issue on the native / dartium side?

[ahe, 2014-10-15 06:45:40]

On 2014/10/13 15:38:44, vsm wrote:
> lgtm
> 
> is there a corresponding issue on the native / dartium side?

Not as far as I know.

I've filed this bug https://code.google.com/p/dart/issues/detail?id=21331 to
track the problem I mentioned above.

[ahe, 2014-10-15 07:37:48]

Committed patchset #3 (id:130001) manually as 41116 (presubmit successful).