ash: Make sure all the sub-popups retain the same height as the main popup.

ash: Make sure all the sub-popups retain the same height as the main popup.

This required a few smaller changes:
 * Refactor some code for creating the detailed view.
 * Change the layout code for the new layout in the mocks.
 * Add a way for re-using an existing bubble instead of creating a new one.

BUG=127430
TEST=aura_shell_unittests.BubbleCreationTypesTest

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=137149

[sadrul, 2012-05-15 04:49:17]

.

[sadrul, 2012-05-15 05:29:27]

.

[Ben Goodger (Google), 2012-05-15 16:07:28]

lgtm