Make Widget::Show() creates active windows.

It is actually what this is doing in practice but only because
SHOW_STATE_INACTIVE implementation is broken and usually creates active
windows.

BUG=None

Review URL: https://codereview.chromium.org/118283003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@243590 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 243590