Reland 270975: [Mac] Unselect generated password when mouse leaves password bounds.

Reland 270975: [Mac] Unselect generated password when mouse leaves password bounds.

> Revert of [Mac] Unselect generated password when mouse leaves password bounds. (https://codereview.chromium.org/282093006/)
> 
> Reason for revert:
> Speculative revert, FormFillLatencyAfterSubmit is failing
> 
> Original issue's description:
> > [Mac] Unselect generated password when mouse leaves password bounds.
> > 
> > In the Mac implementation of the password generation poup, the password
> > row is not unselected when the mouse is moved elsewhere in the popup
> > (e.g. over top of the help text).
> > 
> > The fix is that PasswordSelected() should always be called in
> > SetSelectionAtPoint, not just when the mouse is within the password
> > bounds. The Views implementation happens to work because it has a
> > subview (PasswordRow) which triggers OnMouseExited() when the mouse
> > moves outside of the password bounds.
> > 
> > Also added an optimization that PasswordSelectionUpdated() is only
> > called when the value is actually changed, not every time
> > PasswordSelected() is called.
> > 
> > BUG=114092
> > R=isherman@chromium.org
> > 
> > Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=270975
> 
> TBR=gcasto@chromium.org,isherman@chromium.org,dubroy@chromium.org
> NOTREECHECKS=true
> NOTRY=true
> BUG=114092
> 
> Review URL: https://codereview.chromium.org/287063007

TBR=akuegel@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=271364

[Patrick Dubroy, 2014-05-19 12:04:25]

Committed patchset #1 manually as r271364.

[Adrian Kuegel, 2014-05-19 12:27:57]

lgtm