WebCrypto: Add the KeyPair interface.

WebCrypto: Add the KeyPair interface.

Spec: https://dvcs.w3.org/hg/webcrypto-api/raw-file/tip/spec/Overview.html#keypair

BUG=245025
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=156824

[abarth-chromium, 2013-08-27 23:43:24]

LGTM

Can you add a test that KeyPair correct retains the JS wrappers for the Keys? 
Specification:

1) Have a function that returns a KeyPair object and doesn't keep any references
to anything else.
2) Add an expando property to one of the Key objects in the KeyPair (i.e.,
foo.publicKey.bar = "expando")
3) Call window.gc()   (take a look at tests that use gc.js to see how that
works)
4) Check that the expando property is still there.

[eroman, 2013-08-28 00:02:05]

Done (I believe I have added the requested test)

When you get a chance please also take a look at
https://codereview.chromium.org/23338006/ which this changelist depends on.

[abarth-chromium, 2013-08-28 00:08:46]

On 2013/08/28 00:02:05, eroman wrote:
> Done (I believe I have added the requested test)

Looks great.

> When you get a chance please also take a look at
> https://codereview.chromium.org/23338006/ which this changelist depends on.

Oh, sorry.  Done.  You should add yourself as an OWNER of modules/crypto to make
that sort of thing easier in the future

[commit-bot: I haz the power, 2013-08-28 03:46:08]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/eroman@chromium.org/23617006/2001

[commit-bot: I haz the power, 2013-08-28 06:36:21]

Change committed as 156824