Remove O(n^2) loop in serialized script value conversions

Remove O(n^2) loop in serialized script value conversions


BUG=
R=sra@google.com

Committed: https://github.com/dart-lang/sdk/commit/7ca31f9bbc27497d8386d14530d52a889c94bf71

[Alan Knight, 2016-03-22 00:34:50]

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

[sra1, 2016-03-22 00:54:21]

https://codereview.chromium.org/1817343002/diff/1/sdk/lib/html/html_common/co...
File sdk/lib/html/html_common/conversions.dart (right):

https://codereview.chromium.org/1817343002/diff/1/sdk/lib/html/html_common/co...
sdk/lib/html/html_common/conversions.dart:63: var clones = new
HashMap.identity();
Be careful here.

The implementation of identityHashCode puts a property on the object.
The effect is to modify the data you are serializing.
It might be necessary to change how identity hash codes work.
Is it possible to add a property in such a way that it does not pass through all
the APIs that use structured clones?

[Alan Knight, 2016-03-22 18:00:01]

https://codereview.chromium.org/1817343002/diff/1/sdk/lib/html/html_common/co...
File sdk/lib/html/html_common/conversions.dart (right):

https://codereview.chromium.org/1817343002/diff/1/sdk/lib/html/html_common/co...
sdk/lib/html/html_common/conversions.dart:63: var clones = new
HashMap.identity();
On 2016/03/22 00:54:21, sra1 wrote:
> Be careful here.
> 
> The implementation of identityHashCode puts a property on the object.
> The effect is to modify the data you are serializing.
> It might be necessary to change how identity hash codes work.
> Is it possible to add a property in such a way that it does not pass through
all
> the APIs that use structured clones?

OK, I moved the code to use an identity map down into the Dartium-specific
version, and left the general/dart2js version as is. So it shares less code but
avoids the issue of polluting JS objects with the identityHash property. It's
only really a performance problem on Dartium, on accepting a structured clone.

[sra1, 2016-03-22 18:27:19]

lgtm

[Alan Knight, 2016-03-22 18:28:17]

Description was changed from

==========
Remove O(n^2) loop in serialized script value conversions


BUG=
==========

to

==========
Remove O(n^2) loop in serialized script value conversions


BUG=
R=sra@google.com

Committed:
https://github.com/dart-lang/sdk/commit/7ca31f9bbc27497d8386d14530d52a889c94bf71
==========

[Alan Knight, 2016-03-22 18:28:18]

Committed patchset #2 (id:20001) manually as
7ca31f9bbc27497d8386d14530d52a889c94bf71 (presubmit successful).