Fixes Issues #596 & #982.
Includes the following changes:
1 - Removes the children field from within TabPanel to rely exclusively on
the contained DeckPanel to maintain the child widgets.
2 - Introduces nested unmodifiable classes for DeckPanel and TabBar to
prevent invariant violating changes from being made though getTabBar()
and getDeckPanel().
3 - Expands TabPanelTest to verify the behavior introduced in 2.

Patch by: bobv
Review by: knorton



git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@1010 8db76d5a-ed1c-0410-87a9-c151d255dfc7
2 files changed