[Mac] Unselect generated password when mouse leaves password bounds.

[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

[Patrick Dubroy, 2014-05-15 11:25:21]

Garrett, Ilya, PTAL.

[Ilya Sherman, 2014-05-15 20:23:11]

LGTM

[Patrick Dubroy, 2014-05-16 10:00:58]

Committed patchset #1 manually as r270975 (presubmit successful).

[Adrian Kuegel, 2014-05-16 12:21:33]

A revert of this CL has been created in
https://codereview.chromium.org/287063007/ by akuegel@chromium.org.

The reason for reverting is: Speculative revert, FormFillLatencyAfterSubmit is
failing.

[Adrian Kuegel, 2014-05-16 12:33:52]

On 2014/05/16 12:21:33, Adrian Kuegel wrote:
> A revert of this CL has been created in
> https://codereview.chromium.org/287063007/ by mailto:akuegel@chromium.org.
> 
> The reason for reverting is: Speculative revert, FormFillLatencyAfterSubmit is
> failing.

Feel free to reland this. Apparently it was a flaky test, sorry for reverting.