Move SigninManagerDelegate into the Signin component.

This interface is intended for embedders to supply to the Signin component.
It had been created during an earlier aborted effort to componentize Signin.

BUG=332107
TBR=joi

Review URL: https://codereview.chromium.org/132083002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244139 0039d316-1c4b-4281-b951-d872f2087c98
Blink roll 164835:164850

http://build.chromium.org/f/chromium/perf/dashboard/ui/changelog_blink.html?url=/trunk&range=164836:164850&mode=html
TBR=
BUG=

Review URL: https://codereview.chromium.org/133453002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244140 0039d316-1c4b-4281-b951-d872f2087c98
Update .DEPS.git

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244141 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 244141