[webcrypto] Remove ifdef that is no longer needed.
[webcrypto] Remove ifdef that is no longer needed.

BUG=373917
TBR=abarth

Review URL: https://codereview.chromium.org/345593004

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@176471 bbb929c8-8fbe-4397-9dbb-9b2b20218538

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