Add support for embedders to require authentication before autofilling passwords.

Currently, this feature is only supported on Android devices, but this provides
the basic hooks to allow requiring additional auth before providing autofilled
passwords.

BUG=341492

Review URL: https://codereview.chromium.org/159203004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@250473 0039d316-1c4b-4281-b951-d872f2087c98
14 files changed