[webcrypto] exportKey() now returns dictionary when format='jwk' (CL 1 of 2).

Previously it would return an array buffer of the JSON.

This corresponds with the recent spec update:
https://dvcs.w3.org/hg/webcrypto-api/rev/f61017a76a5d

BUG=373917, 245025
R=rsleevi@chromium.org

Review URL: https://codereview.chromium.org/334333004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@277884 0039d316-1c4b-4281-b951-d872f2087c98
1 file changed