Refactor SpeedTracerLogger to use Event objects for controlling start/stop

Review at http://gwt-code-reviews.appspot.com/704803

Review by: zundel@google.com

git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@8500 8db76d5a-ed1c-0410-87a9-c151d255dfc7
46 files changed