Check for null prototype in isJavaScriptSimpleObject

Check for null prototype in isJavaScriptSimpleObject

BUG=
R=floitsch@google.com, sra@google.com

Committed: https://code.google.com/p/dart/source/detail?r=43340

[Alan Knight, 2015-01-29 01:15:25]

alanknight@google.com changed reviewers:
+ sra@google.com, terry@google.com

[Alan Knight, 2015-01-29 01:15:26]

This is Florian's fix in https://code.google.com/p/dart/issues/detail?id=21782

It seems sensible to me. I would be more comfortable if we had a test for it
(that didn't involve Polymer) but I'm not sure how to exercise it, so
suggestions welcomed.

[sra1, 2015-01-29 02:32:57]

Add a test case to  tests/html/postmessage_structured_test.dart - that doesn't
require polymer.

Clone this test:

    test('js-to-dart-postmessage', () {
      // Pass an object literal from JavaScript. It should be seen as a Dart
      // Map.

      final JS_CODE = """
        window.postMessage({eggs: 3}, '*');
        """;
      var completed = false;
      var subscription = null;


and change

      final JS_CODE = """
        window.postMessage({eggs: 3}, '*');
        """;


to something like:

      final JS_CODE = """
        // Call anonymous function to create a local scope.
        (function() {
           var o = Object.create(null);
           o.eggs = 3;
           window.postMessage(o, '*');
         })();
        """;

https://codereview.chromium.org/886673002/diff/1/sdk/lib/html/html_common/con...
File sdk/lib/html/html_common/conversions.dart (right):

https://codereview.chromium.org/886673002/diff/1/sdk/lib/html/html_common/con...
sdk/lib/html/html_common/conversions.dart:397: JS('bool',
'Object.getPrototypeOf(#) === null', value);
Please CSE, the compiler can't do it:

{
  var proto = JS('', 'Object.getPrototypeOf(#)', value);
  return JS('bool', '# === Object.prototype', proto) ||
         JS('bool', '# === null', proto);
}

[floitsch, 2015-01-29 11:44:14]

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

[floitsch, 2015-01-29 11:44:15]

LGTM with stephen's comments addressed.

[Alan Knight, 2015-01-29 22:52:45]

The test with postmessage didn't work, as it automatically added the Object
prototype to the data, but added one with the same idea using a MessageEvent.

https://codereview.chromium.org/886673002/diff/1/sdk/lib/html/html_common/con...
File sdk/lib/html/html_common/conversions.dart (right):

https://codereview.chromium.org/886673002/diff/1/sdk/lib/html/html_common/con...
sdk/lib/html/html_common/conversions.dart:397: JS('bool',
'Object.getPrototypeOf(#) === null', value);
On 2015/01/29 02:32:57, sra1 wrote:
> Please CSE, the compiler can't do it:
> 
> {
>   var proto = JS('', 'Object.getPrototypeOf(#)', value);
>   return JS('bool', '# === Object.prototype', proto) ||
>          JS('bool', '# === null', proto);
> }

Done.

[sra1, 2015-01-29 23:30:15]

lgtm

[Alan Knight, 2015-01-30 17:42:16]

Committed patchset #3 (id:40001) manually as 43340 (presubmit successful).