[webcrypto] Make all of the crypto.subtle method failures asynchronous.

[webcrypto] Make all of the crypto.subtle method failures asynchronous.

This matches the spec update https://dvcs.w3.org/hg/webcrypto-api/rev/4bd9e8dbe699

Background: The crypto.subtle methods all return a Promise. Rather than throwing exceptions for certain types of invalid/unsupported input but not others, the Promise is now consistently rejected. Web IDL errors are not affected and will still throw exceptions like before.

Specifically this changelist makes it so:
 * No longer throws NotSupportedError [1]
 * No longer throws when given an unrecognized/unsupported KeyFormat or KeyUsage

[1] It used to do this when the algorithm name was unrecognized, or the algorithm didn't support the requested operation.

BUG=245025
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=167611

[abarth-chromium, 2014-02-21 07:44:47]

lgtm

[commit-bot: I haz the power, 2014-02-21 07:45:04]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/eroman@chromium.org/170243007/1

[commit-bot: I haz the power, 2014-02-21 10:54:51]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-02-21 10:54:52]

Retried try job too often on win_blink_rel for step(s) webkit_tests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win_blink_...

[eroman, 2014-02-21 19:27:28]

The CQ bit was checked by eroman@chromium.org

[commit-bot: I haz the power, 2014-02-21 19:27:43]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/eroman@chromium.org/170243007/1

[commit-bot: I haz the power, 2014-02-21 20:20:00]

Change committed as 167611