[webcrypto] Remove code conditional on !defined(WEBCRYPTO_HAS_KEY_ALGORITHM).

This is the sister change to r253463 to remove the old API once the blink changes have rolled into chromium.

BUG=245025
TBR=rsleevi

Review URL: https://codereview.chromium.org/182073002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@254080 0039d316-1c4b-4281-b951-d872f2087c98
8 files changed