Password bubble: Create subviews for ManagePasswordsBubbleView.

Password bubble: Create subviews for ManagePasswordsBubbleView.

Same idea as we've done for ManagePasswordItemView: separate subview
classes make it simpler to change the content and to understand where
the content is coming from.

After this CL, it will be a simpler addition to shoehorn in a blacklist
confirmation screen in the same way that we've done undo for the item
views.

-----------------------------------------------------------------------
This is a reland of r267213, which was reverted in order to revert a
different patch (r266859) due to LSAN errors. The original review is
https://codereview.chromium.org/255903006/
-----------------------------------------------------------------------

BUG=261628
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=268179

[Mike West, 2014-05-05 07:10:38]

Vaclav, would you mind stamping this reland of a patch that was reverted in
order to revert that other patch I've spent 3 days trying to land? :)

-mike

[vabr (Chromium), 2014-05-05 07:47:54]

Stampity stamp. :) LGTM

[Mike West, 2014-05-05 13:21:08]

The CQ bit was checked by mkwst@chromium.org

[commit-bot: I haz the power, 2014-05-05 13:22:46]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/mkwst@chromium.org/266973002/1

[commit-bot: I haz the power, 2014-05-05 14:55:16]

Change committed as 268179