core/platform/chromium/support/WebCrypto.cpp cannot depend on modules

Just needed another layer of virtual.

R=abarth
BUG=301947

Review URL: https://codereview.chromium.org/25417002

git-svn-id: svn://svn.chromium.org/blink/trunk@158602 bbb929c8-8fbe-4397-9dbb-9b2b20218538