Move RestoreOnStartupPolicyHandler to live in chrome/browser/sessions.

Also add unit tests, as none existed.

This facilitates the refactoring of chrome/browser/policy into a layered
component.

BUG=271392

Review URL: https://codereview.chromium.org/28853004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@230491 0039d316-1c4b-4281-b951-d872f2087c98
Pass apps transparentBackground flag through to widget creation

R=wez@chromium.org
BUG=309933

Review URL: https://codereview.chromium.org/36133002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@230492 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 230492