[webcrypto] Restrict public exponent for RSA key generation to 3 or 65537.

OpenSSL can hang when given invalid values for the public exponent so do a whitelist validation approach to avoid this.

For compatibility reasons the same restriction is applied to the NSS implementation.

BUG=381844,245025

Review URL: https://codereview.chromium.org/329673002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@276658 0039d316-1c4b-4281-b951-d872f2087c98
7 files changed