Following up on https://jira.springsource.org/browse/ROO-1276, here's the proposed alternate design, separating the "keep history and places in sync" and "map places to/from history tokens" concerns into a concrete PlaceHistoryHandler class and a PlaceHistoryMapper interface whose implementation can be generated based on annotations. This patch superseeds http://gwt-code-reviews.appspot.com/824801/show and integrates the changes from http://gwt-code-reviews.appspot.com/827801/show (if it weren't the handler -> mapper renaming, they could have been kept separate). Derived from http://gwt-code-reviews.appspot.com/845802, but without the ActivityMapperGenerator bits. Review by: rjrjr@google.com Patch by: t.broyer@gmail.com git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@8817 8db76d5a-ed1c-0410-87a9-c151d255dfc7