Add a pointer to the supervised user dashboard to the Settings page

It's hard for managers to know where to manage their users. Add a link to the
dashboard under the Users section on the Settngs page, for users who are
managing one or more supervised users.

BUG=298836

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=231873

Review URL: https://codereview.chromium.org/27715002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@232558 0039d316-1c4b-4281-b951-d872f2087c98
Add new UMA histogram SB2.InterstitialActionDetails

This adds a new UMA histogram (SB2.InterstitialActionDetails) to track two things:

1) Do people react differently to warnings on sites they haven't visited before?
2) Do people react differently to cross-site warnings?

BUG=
R=mattm@chromium.org

Review URL: https://codereview.chromium.org/48903016

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@232559 0039d316-1c4b-4281-b951-d872f2087c98
Check sourceFrame before dereferencing during dispatching of postMessage.

BUG=275913

Review URL: https://codereview.chromium.org/55013002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@232560 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 232559
Show keyboard/toolbar on 3-finger swipe up/down

3-finger swipe up shows the soft keyboard. 3-finger swipe down shows the
toolbar, and 3-finger tap injects a middle mouse button click.

BUG=293703

Review URL: https://codereview.chromium.org/55613002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@232561 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 232561