[webcrypto] Update to use the KeyAlgorithm.

The WEBCRYPTO_HAS_KEY_ALGORITHM ifdef will be introduced by https://codereview.chromium.org/179353002/ on the blink side. 

This patch needs to land first in order to make the API changes on blink side without breaking the build. Sigh for non-atomic blink/chromium commits.

BUG=245025

Review URL: https://codereview.chromium.org/178073007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253463 0039d316-1c4b-4281-b951-d872f2087c98
10 files changed